Just picked up an '87 extended cab with the 2.9l auto. Seems to be in pretty good shape for it's age except for the fact that is has an idle issue that comes and goes every minute or so. Runs fine for a minute, then stumbles for about 30 seconds, then will run fine again for a while. PO said he put a gauge on fuel system that read 34 until idle would stumble, then would increase to 40. So he ordered a fuel pressure regulator which I installed last night. Didn't help. Will probably check the basics this weekend (i.e. air-idle bypass, throttle body, fuel filter, etc.) If you guys have any suggestions or have had a similar problem, would be greatly appreciated. Will also look for code reader this weekend, any suggestions on that would also be appreciated.

 

the basics are what you should have done first...clean everything, pvc, iac, tb, before you start buying everything new, for sure throw a new filter on it, then maybe use some seafoam, then after you run it for awhile put some nice wires and plugs on it....could just be getting old, the older it gets, the harder to keep the idle like new, that's just life....how many miles are on it?

 

Readin ya loud and clear. Cleaned throttle body and iac tonight, friend happened to have egr in box, was gonna change that out tonight, but.....snapped lower bolt off in the intake. So will be drilling that out tomorrow. And Sea Foam is a great idea....love the stuff....What are your thoughts put half a bottle in with a fresh tank and let it sit in the driveway idling for a while, then take it for a spin?

Thanks

 

i have used fuel additives on a quarter tank for a higher concentrate, never had problems, but don't do that too much too often....ive seen it used many ways...whatever floats your boat....

i just did the lower intake gasket on my truck ( bolts loosened and blew the silicone )last weekend along with a crap load of other stuff, fun times...also have you taken a peak at the spark plugs? Was the iac full of crap, what did the tb look like? there's only so much you can do to fix a bad idle....sometimes the motor mounts and tranny mounts can cause a horrible idle...do all that fun stuff and see what happens...

 

put half a bottle in the tank and slowly feed the rest of the the bottle into your brake boost line at an idle....go slow when you pour it in, you don't want to hydo lock your engine, it may die when the sea foam makes it to the combustion chamber at first but try again and pour slow......

 

Iac actually looked really good, tb had a lot of build up, so I cleaned it as well as I could. Gonna work on getting broken bolt out of intake and new egr on today, then will probably sea foam it and see how it's doing. Thanks again.