TBI question

[Mac1978]

Hey All,
I have a question thats probably just so painfully obvious, that i cant figure it out! On my 88 jimmy, when you rev it a bit in neutral, it pops and backfires a bit as the rpm decrease.It is also seeming to be a bit sluggish on acceleration. I just did an engine swap, and it did it with the old engine, too. I am assuming its probably the tps, or maybe even the throttle body itself. Has anybody else had this problem? Thanks

[scotts62]

Originally Posted by Mac1978

Hey All,
I have a question thats probably just so painfully obvious, that i cant figure it out! On my 88 jimmy, when you rev it a bit in neutral, it pops and backfires a bit as the rpm decrease.It is also seeming to be a bit sluggish on acceleration. I just did an engine swap, and it did it with the old engine, too. I am assuming its probably the tps, or maybe even the throttle body itself. Has anybody else had this problem? Thanks

A friend of mine had one of those (im not sure what year though) but it was the same style as yours, but anyway it was doing a sumilar thing as what you are explaining, we changed intake gaskets, injectors, checked timing miltiuple times etc etc, and it ended up being an ECM. we guess that water or something got in it... (check a you pull yard and you can usually get one for 25-35 bucks)
But that may not even be the problem but its worth checking if you have done everything else. Good luck

[Mac1978]

did it idle high, too?

[scotts62]

no it wouldnt even run at times but when it did it ran like it was on 3 cylinders and sputtered and back fired

[Mac1978]

sounds like a bit different problem, then

[ca180]

Sounds like a vacuum leak