I have a 1991 isuzu pickup with a factory 2.6L engine. When the truck is dropping from a high idle like coasting to a stop with the clutch pushed in the trucks idle will surge, I changed the TPS and this had no affect. Anyone have any ideas of what my problem might be? Thanks, Justin

 

that would be your idle control valve. your truck is revs up an down. try taking it off an cleaning it out. they get gummed up an gunked up by oil. try some carb cleaner thru it. also if you dont want to take it off. shoot some carb cleanner down the intake. that will do the trick as well. make sure to use the straw that come with the cleaner. you dont realy want to get it on your air mass meeter. slip the straw in past the air meeter with the truck running at an idle an just spray until the truck dies then let it sit for ten mins fire it up, an spray little shots till your can is empty. an all sould be well, if not you need an icv .