Got a question. It doesn't happen all the time, maybe a couple of times a week. Sometimes when I start the truck It will go through it's rev's while it warms, then once the rpm's come down to around 750-800 it lope excessivly from 500-800. Give it throttle and it goes away. Let off and comes back to 750-800 then starts loping at 500-800. I don't believe it is electrical, it's not a hard miss, but soft. I just changed my plugs and #1 had some residual fuel on it. Does anyone know if an injector that is bleeding out could be the culprit. Again it only does it occasionaly. But my gas mileage around town is around 9-11 mpg. Truck is ext.-cab, 302, auto, 2wd. Excellent shape, picked the truck up from an old man back in Jan 06, everything else is in good order. Help.

 

I'd start with the simple things first. A build up of carbon / oil residue in the throttle body right behind the throttle blades will cause an erratic idle as well as a gummed up IAC (idle air control). I clean mine by removing them from the engine and using an aerosol type throttle body cleaner and soft tooth brush. Some throttle bodys have a warning sticker not to clean them due to harsh solvents which may damage plastic or coated parts. Use your own judgement. You'll need a fresh throttle body gasket and IAC gasket to reinstall them. I'd also look for a vacuum leak or clogged pcv system. If none of this helps, I take it to your favorite mechanic so he can scan it for codes, then go from there.

 

thanks, i will go ahead and take the throttle body off and give everything a clean out. do you know if an injector bleeding out could cause this or not. again thanks for answering.

 

the injector shouldn't, as if it were bleeding out, then the rpms would stay consistently high as the engine would be getting more fuel. definetly agree with jade though, start simple.

 

i'll go ahead and do as jade said and hopefully that will get me something. thanks