Engine/Transmission (1994 - 1998) Stumbling

[gcorron]

Sometime tomorrow I have to crawl under the hood and work on this, but you guys might have some insight or previous experience here.



I was waiting in line at our landfill yesterday, and the truck "stumbled" a few times. When I went to turn the corner at the dump, it cut off completely.



If I put it in neutral, or park, it would sit there purring like a kitten, but in any gear, it stumbles and maybe shuts off unless you are under power.



I have a bad sending unit in the tank which will be replaced soon, real soon, and obviously air leaking into my fuel lines because it is a bear to start if it sits for a day or so, but the stumbling thing is new. I will replace the tank lines when the sending unit is repaired.



Any thoughts on this new problem?



George

 

[SFPADGETT]

First, please fill out your profile and list the vehicle, it will help with suggestions and problem finding. Assuming it is a 12v, 98 or older, then check your idle speed, it may be too low. The Factory Service Manual (FSM) will give the correct RPM for your year.

 

[gcorron]

Went to edit my profile. Truck info was already there. Not sure how to add it to my signature block?



Idle speed is about 750, it's been there since I set it in the fall. Overflow valve is fairly new with low miles.



97 4 wheel drive, automatic 157k, kdp long fixed, Larry B's starter contacts.



George

 

[SFPADGETT]

We set our idle speed at 800-850, in drive, A/C on and engine warm. When set to the low end per FSM of 750, we sometimes have stalling / stumbling problems.



When you set the idle speed in the fall, did you also have the A/C on?



Also, the adjustment bolt does tend to slip (we adjust ours about once a year).



Sometimes, very rare, we have gotten "bad" fuel, where the truck doesnt want to run well--it usually clogs the fuel filter and we have to replace it.



Could the change from "winter" to "summer" fuel be a problem? Here in GA we notice a difference



I would check the idle speed first and adjust as needed

Fuel Filter second,

Leaking fuel lines

Fuel at stations that use alot of fuel, ie. good turnover of fuel in their tanks

 

[gcorron]

Thanks for the reply. Yup, we always have the A/C on, but it was not when it stumbled. I thought the fuel leak had gotten worse, but it ran fine under power and idled perfectly.



I'll let you know, I have gone a longer than normal period between fuel filter changes, but where I buy my fuel is very clean and the filters always are clean as well.



Thanks again, unfortunately, son just stole my camera for a quick trip to Niagara Falls (he always wanted to see it, and found someone else that did too) so whatever I find pictures are not in the future!



I'll check the adjustment screw, it could be!



George

 

[gcorron]

OK, rain, old age, all other manner of excuses, but I just got the unit out today, after ordering a sending unit, only to find out... ... it ain't the sending unit!!!! I was taking my time, I'm making a power point so the forum can have it, so I have pictures. All will be posted when complete. yup, I had a leaking fuel line, but when I got the unit out... ... the sheet metal was completely rusted apart! #@$%!



The entire thing was in 2 pieces, and laying on the bottom of the tank. Drop back and order the whole thing, should be here Wednesday, so I can finish and report shortly, I hope. The strainer was very clean, as you can see in the picture, there is no water in the tank, nor evidence there ever was, yes, I have paste.



I'm guessing fuel additives ate this thing, and no, I very, very rarely add them.



Just thought i'd pass along, that sometimes it is not the fuel sender, which still works well when not laying on the bottom of the tank sideways!!!!



George



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