I'm going to describe the problem, and then give my diagnosis and treatment regimen. What I need is to know if

A) I'm on the right track

B) Is there a better way to fix it

C) Am I an unGodly danger to myself (or others)

Here goes. Dodge Dakota 1988, 6 cyl., throttle body injector. Truck runs fine for about 30-45 min, then (occasionally) it will *cough*. Sometimes once, sometimes a few times, sometimes it'll do it, then a few minutes later it'll do it again. The effect is just as if it had a little *cough* - it jerks, no noise of a backfire or anything, just like a skipped firing or something. No elec. flickering, or other surrounding phenomenon. Just a jerk/cough. Like a hiccup.

It only does it at highway speeds. Never say never, but so far it does not *cough* at lower, in-town speeds, and never in idle. It is an isolated event or series of events, and is not rhythmic, nor is there any sort of warning noise or anything. Just driving along at 65 (interstate) and *cough*. Always scares the piss out of me, because it feels like it's going to just quit running (and I'm nearly always in traffic!), although it never has; however, occasionally it has done it in such a way that it takes a second to get gas again, although luckily it's been on the home run at night with no traffic.

Here's my guess - crap in the gas tank. We've replaced the fuel filter before, and it seems to stop it for a while (although this is not always an everyday thing), but it rarely lasts. It starts up bad after we let the gas get low instead of keeping it a half or above. Run a few bottles of Gum-Out, but if there's crap in the tank, I'm just cleaning it out as it sucks it in, which seems to be the case. No hiccups a day or so afte the treatment, then *cough*. How long should a fuel filter last anyway, given two to four hours driving most days, mostly highway miles? (Only thing that really sucks about country life - long commutes!)

Here's my problem: Something tells me I'm going to have to take off the tank and either replace it or do a manual swish and rinse with this big ol' thing. I really do not want to do it myself (terrified of fire), but am leary of how much it would cost to have it done. There are also time constraints - it is the only vehicle and we leave in almost exactly one month to drive over the Blue Ridge fully loaded. REALLY, REALLY do not want to *cough* all the way through the mountains fully loaded with stuff and animals and with free-wheeling transportation specialists nipping at my heels.

Any help out there? Is there a better way? It's had new plugs, coil, rotor, full-works tune up. Engine light comes on when it hiccups really bad, and code check always says fuel injection system.

Other possibly unrelated quirks - hesitates when you just barely press on gas. Idles fine. Most likely vacuum leak. Hopefully replacing the hoses will fix that if I'm lucky. If I'm not, it's the intake seal (wheee).

Had a bad day few months past where it just quit going while pulling out into traffic (why is it always while I'm pulling out into traffic!). No gas, nada. Eventually got it to limp home, but would balk everytime I had to push gas (pulling out of a stop sign), although it held steady at speed. Thinking either temporary clog in catalytic converter, or more of this with something big getting sucked up against the fuel filter, then releasing when the big sucking (getting started) was over. Next day it was fine.

So, whaddya think? Am I getting warmer? WIll I burst into a billowing ball of flame running down the highway? Will I burst into flame just by actually touching the gas tank? (Hope I get over that fear - am planning on taking some courses in automotive repair when I go back to school - guess why!) Am I missing an obvious problem or quick fix? Or does my entire life suck, except for my fuel system?

-- Soni (thomkilroy@hotmail.com), February 16, 2002

Answers

Soni, Here's my thought. My shelby charger (84) was having a similar problem and it turned out to be the charcoal canister going bad and sucking little chunks-o-charcoal thru the vacuum lines and into the carb. clogging the little metering holes. I took the top of the carb off and cleaned out the float bowls blew out the vacuum lines back to the canister. I took an old pair of panty hose and filtered both ends of the line...never had a problem after that... might check to see if the setup is similar on your Dakota (not too familiar with those)..

-- scott (sbitzer@columbus.rr.com), February 16, 2002.

Oh no not a billowing ball of flame, it'll be a little bit slower than that and I'm sure the cab will contain it for at least a few minutes! Vacuum leaks cause the oddest behavior in vehicles, the first thing to check. Your fuel pump could be cutting out, or it's getting a flawed signal from your computer. I doubt both really. I doubt it's crap in your tank too. Unless you really get poor quality gas your filter should be fine. What do you use? Have to changed where you buy gas? It sounds a little like water in the gas except it's only at high speed. Kleenflow makes a non methylhydrate gas line antifreeze to remove water that works very well. When was the thermostat changed last? Cheap to replace and if your engine isn't at the right operating temp it'll cough too. My wifes little Dodge car ran like total crap before I changed the thermostat, now it's actually fun to drive. I'm no mechanic either but I'd leave the tank alone until I'd tried a few other things, partly because it's one ugly job, but mostly because I doubt that's the problem.

-- Ross (amulet@istar.ca), February 16, 2002.

doesnt sound like a fuel problem,, more like electrical,, or maybe vacuum. Have you been able to pull codes from it ?

-- Stan (sopal@net-port.com), February 16, 2002.

I am kidding about the flames Soni.............. you knew that right!! :^) Good luck!

-- Ross (amulet@istar.ca), February 16, 2002.

Don't think pulling and cleaning fuel tank is the answer. Had a problem similar to what you describe a few years ago, I had to replace all the rubber hose connections at the top of the fuel tanks, and at the tank "T" connections (twin tank truck) they were weather cracked and would not leak fuel but would let fuel pump lose suction, and this would cause truck to lose power by starving if for fuel, but it only happened at half tank or less of fuel. If your fuel pump is in the tank though, this won't be the problem. Also, if I suspect water in the fuel in my gas rigs I use 45 cent bottles of alcohol from the dollar store.

-- gary wayland (wayland@brightok.net), February 16, 2002.

What code does it set when the ck. engine lite comes on? I don't think it's in your fuel system and I would stop wasting my money on fuel cleaner. Some of this stuff does more damage than good on fuel injection systems. I know you said it was tuned up but how long ago and what quality parts. I have seen brand new tuneup parts from the auto supermarkets that didn't work properly. Does this truck have an auto trans? Take a spray bottle with some water and spray the spark plug wires with it while someone in the truck revs the engine while in drive(if it's an automatic). Don't get too carried away you only have to load the engine. If it's a manual trans wet the wires and drive it up hills if possible. If wetting the wires makes the problem occur you probably have bad plug wires. Replace all your vacum hoses before you do anything. I don't think you'll have any need to remove the fuel tank. The tank is probably plastic on this truck and unless someone dumped something in it I don't think you have a problem there.

-- Emil in TN (eprisco@usit.net), February 16, 2002.

No real good help here, but it seems to be a Chrysler thing, had an older Cordova that did the exact same thing Soni, had hardly any miles on it, but was 7 years old, drove us absolutley crazy and about got us killed doing it's thing in front of oncoming traffic! Nothing makes your heart stop faster than a vehicle trying to "die" on you in the face of a barreling ever closer semi truck!

It's not a fuel supply problem, or dirty tank, but those other hints at vaccuum supply and electrical are probably very close. We spent way too much money on trying to have experts at Chrysler fix the problem, they couldn't, so we sold the car before it killed us.

-- Annie Miller in SE OH (annie@1st.net), February 16, 2002.

Just a couple of thoughts (and I'm by no means a mechanic) - it might have something to do with the oxygen sensor and/or a stopped up catalytic converter. I'm not sure how to check either one of those without replacing them, but maybe someone could help out there. Either problem causes the *cough* you mentioned and gets worse as time goes on. Maybe this will help a little - good luck!

-- Phil in KS (pemccoy@yahoo.com), February 16, 2002.

Try posting your question at cartalk. Quite a few knowledgeable mechanics help folks there.

Out of curiosity does your problem happen only in the winter or get worse during the winter or when the weather's cold?

-- Darren (df1@infi.net), February 16, 2002.

Make sure the plug ins that supply the fuel pump are not burnt and that the gas cap is ventilated.

-- mitch hearn (moopups@citlink.net), February 16, 2002.

Check electrical connector to fuel injection system.

-- David R In TN. (srimmer@earthlink.net), February 16, 2002.

Fuel line problems (especially where rubber meets steel), and most likely back by the gas tank. Leave it long enough and it will be easy to find, because it will leak.

-- Chuck (chuck@areiax.com), February 17, 2002.

Well' I am a mechanic but fixes cars on telephone lines is like waving lanterns at runaway trains. But here is where I would start----- I would check the fuel pressure both before and after it leaves the fuel pressure regulator(you'll need some specifications for this out of a repair manual or get them from Dodge)--if that's ok than I would try it a week without a gas cap becuase a faulty cap can give you the result you described. Next I would try the EGR valve disconnected(this will trigger a check engine light but you can put it out after your done testing by removing the battery terminal for 30 seconds. Finally, and this is what I really suspect, you may have lost the electronic advance on your distributer and only a dealer diagnostic will find this problem--cost should run 50.00 for a diagnosis but get it in writing. Hope this helps !

-- Joel Rosen (JoelnBecky@webtv.net), February 17, 2002.

What a great list suggestions, and all of them are great. I once had a truck that acted much the same as yours. At slow speeds it ran fine, but as soon as I tried to go to highway speeds it would die off, almost dieing. Here is a question for you, to your knowlege, has any one at any time ever siphoned gas from your fuel tank? If so your tank has tiny slivers of the hose that was used to do the job inside of your tank. What has happened is when the hose was pulled out it scraped over sharp edges in the filler tube of your fuel tank. What I think is some of the slivers has made it through your fuel system and has partially plugged the internal filter of your carb. allowing you fuel at low speeds, but closing off the flow of fuel at high speeds. Where your fuel line connects to the carb. remove the fuel line, remove the filter you find inside, look and check for any material inside of this area, clean it out if necessary, and re hook the fuel line with out the filter. Take the truck out for a run and see if this fixed the problem, if so buy a new filter and toss the old one. To ensure you have most of the garbage out of your fuel tank, disconnect the fuel line from the fuel pump and drain your fuel into a container, run this fuel through a filter and countinue to recycle about 5 gal. of this fuel through the tank till you are satisfied the tank has been flushed fairly well. Once this has been done reconnect the fuel line to the pump, and after filtering the fuel pour it back into the tank and motor on.

-- Rusty (brookdale@qwest.net), February 19, 2002.

Being quite familiar with Dodges, and Fuel tanks in particular... My very best guess is that your fuel pump is going bad. The dakota has a plastic tank, with an internal fuel pump. Sometimes (blue moon) the sending unit will get plugged and cause a fuel pump bad like symptom. But, heres why this is my best guess: Fuel tank above 1/2 symptoms clear up... this is because the gas in the tank has a cooling effect on the internal tank pump, below 1/2 and the pump is not submerged. Skips at high speeds: this is when the most is asked for from the pump- not idle when the engine is drawing little fuel. Dont be afraid to drop the tank, ther not too much to it, and the risk of fire is not that great (just dont chug on a stoogie while dropping er!). Wait till the tank is near empty to drop it- its so much easier. On tyhe dakota of that yr, there should be a large, white round thing with all kinds of hoses sitting in the top of the tank this is the sending unit. Loosen the stainless steel round clamp , and gently tug on the unit to losen the rubber seal- it will come free. As you take the unot out of the tank, dont yank, just gently turn it so not to reak the float. The unit itself will have pipes wrapping around in cork screw fasion. The pump sits in the middle of this. youll figure out how to get the pump out- its strait forward. This fix is a 6 hour job for someone with no experience, but a half way decent set of tools.

-- Kevin in NC (Vantravlrs@aol.com), February 21, 2002.

I really think you got problems with your vacum canister or lines. Try to clean the ports where the hoses connect to the canister. If thats the problem replace the hoses and canister. I had the same problem with my Cheverolet Malibu. It could also be that someone put somthing in your gas tank like a little but of sugar and it carmolized in the lines. I had someone do that to me. If thats the case you might as well get ride of your truck and look for a newer one! Its very costly to get that type of repair. You should also try to replace the thermostat... if the temp is going up when it hesitats or if you can't remember when it was last replaced. U should try to take off the gas line to the tank and hook it up to a five gallon or little bit larger gas can. Run the truck for a hour or so and see if it hesitats. Put fresh fuel in the gas cans when doing this. Recomend a high octane fuel! If it is not the tank then I would replace the fuel pump, hoses, filter, and check that the computer is telling the pump to run at the apropriate time and rpm. If its the computer MOST LIKLY it will be expensive! If you want to keep the truck and it is the computer i would get it from a junk yard. I hope you get this project fixed! Good luck!

-- Eric Struebel (estruebe@yahoo.com), April 17, 2002.