1988 chevy full size hesitation.

[Doodle]

This old piece of shit has been sitting for a long time,the engine internally is fine.


It will idle ok for a second,then surge up or down..sometimes to the point of stalling sometimes not..under throttle anywhere from 1/8th to 3/4 it almost doesn't respond at all. If I tap and tease it to get it rolling then it will pick up somewhat,but still hesitating,cutting out nearly dead,but still running. If i give it it full throttle it will bog for about 2 or 3 seconds then rev enough to drive,but still prolly half the power it should have..I've cleaned the throttle bodies with some ether,added fresh gas..anyone else had this problem..Just trying to zero in on what exactly it might be before i start throwing expensive parts at it.

[budweezy]

Quote:

Originally Posted by Doodle This old piece of shit has been sitting for a long time,the engine internally is fine. It will idle ok for a second,then surge up or down..sometimes to the point of stalling sometimes not..under throttle anywhere from 1/8th to 3/4 it almost doesn't respond at all. If I tap and tease it to get it rolling then it will pick up somewhat,but still hesitating,cutting out nearly dead,but still running. If i give it it full throttle it will bog for about 2 or 3 seconds then rev enough to drive,but still prolly half the power it should have..I've cleaned the throttle bodies with some ether,added fresh gas..anyone else had this problem..Just trying to zero in on what exactly it might be before i start throwing expensive parts at it.

Did you clean the IAC valve? Also verify your TPS sensor is not sticking and has increasing voltage as you give it gas. What motor is in it? If its TBI motor those main injectors tend to get stuck a lot when the trucks sit. They aren't like normal injectors they are variable rate injectors and have a tendency to screw up.

[reds919hornet]

surging up and down at idle might be a vacuum leak. this could also throw off you map sensor which will throw off your throttle response. map reading low it will not give it enough fuel. fuel pressure could also be low.

[budweezy]

Quote:

Originally Posted by reds919hornet surging up and down at idle might be a vacuum leak. this could also throw off you map sensor which will throw off your throttle response. map reading low it will not give it enough fuel. fuel pressure could also be low.

Good call!!! I've seen the plastic nipples on the MAP sensors crack and break.

[dlish]

fuel filter?

[WHEELIE]

o2 Sensor

[nj636]

check engine light on?

[outcastracing]

yea sound like vacuum

[anarchist35]

if its a vacuum leak u can shoot ether around the vacuum lines, and if it revs up more with a shot, you just found ure vac leak. lots of vac lines to crack on that motor.

[maverickxp]

Vac line is the most probable on that engine. Like anarchist said spray starting fluid around the engine and see if it revs up