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Need Suggestions Please

JS91

JS91

New Member
I have a 91 GT that has a miss under part throttle and when I let off the accelarator. It misses and jerks really hard. During normal acceleration there is no problem at all. At WOT it runs perfect as well. Not sure where to go with this. Thanks.
 
I have not been able to find any vacuum leaks and the check engine light flashed on for about 30 seconds and went back off. It's not showing any codes right now.


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Nothing more than a suggestion but you might check where the PCV valve goes into the lower intake, my rubber grommet that held the PCV valve was wore out and the PCV valve came out of the rubber grommet causing one heck of a vacuum leak.

Are you using a code scanner or counting the light flashes when you say it's not showing any codes right now?
 
Thanks I will check the PCV this evening. I'm using a cheap scanner from the local parts store to check codes. The only thing I get is smog related but it's all deleted from the car.


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Start from there and work your way back....I found my AIC motor was really carbon'd up and most everything on my 89 was oem when I got it. Its not that your going in the wrong direction its just that your going to have to go that route anyways if everything on your engine is oem. When I put on a new coil pack a few years ago I thought I turned the hp up by 30 percent. It's a long but cheap road your going down now,most everything I needed I got at my local parts store. Like you said "the scanner" was the hardest to get my hands on. The only thing that it found was O2 problems. If you haven't tried to get the PVC valve out yet and that small oil screen and that gromment, take my advice and push a shop rags or small towel between the fire wall and back end of the intake manifold.... I dropped the new PVC valve and like most things I drop in the engine bay it never hit the floor. So I had to jack the car up and pull off the right front wheel. The PVC valve was resting on the trans lines....just laughing at me the whole time...There isn't much more then those few things after that. I even noticed a change in engine idle when I got a new Spout connector.....still laughing at that name!!!!
 
Thanks for the help guys. Sorry, I have been really busy the past couple days and haven't been able to look at the car at all. Hopefully I can get the codes again this evening and post those here for everyone to look at. I afraid this is going to turn into changing every sensor on the car until it is fixed.


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yep... there was a few times I thought I licked it but that annoying "check engine" light kept popping on...after the new coil pack and O2 sensors it ran much better. When I swapped out the 65 amp alternator for a 90 amp one, it was an even bigger doing in improving the idle. I think the 10% ethenol in the gas has a hand in some of the problems I was having, I don't get to drive it as often as it should so I believe the gas does break down and cause heck with the emissions check list on the OBD...
 
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