i have an 87 gxl and the car hesitates at around 3k and 5k rpm, ive tried a few things, grounding kit, ran more power to the alternator and starter, just did a compression test both rotory housings are 90psi, so the engines still good, i can hear an exhaust leak and im planning on replacing all the gaskets, any other suggestions what could be causing the hesitations?

what about the basics like checking the resistance of coils per FSM spec? condition of plugs? plug wires?

i did the full tune up on it, its running new ngk plugs and wires

You know...I grounded my injectors and replaced the fuel filter and changed the plugs and I'm STILL getting the stutter.



Are you backfiring? I was...big time. I started running premix (but haven't removed the OMP just yet) and it seemed to make a big difference. Granted, the hesitation is still there, but it's better. I think maybe we need to get our injectors cleaned and flowed. does anybody here know the best place to go for this?

http://www.witchhunter.com/



Excellent service and the lowest price I've seen to date.

i would order a second set of used injectors and have those done, so that you are not with out a car. or just put new ones in.

Is it N/A or turboed?

NA, i also tried running an extra ground to my pressure sensor, i heard that it helps on turbo cars running that ground to the boost sensor, no luck with my car tho

sounds like your aux ports and your vdi arent being opened... its an 87 so its using backpressure from the exhaust. is your split air pipe hooked up?



usually 5/6 ports open around (i believe) 3800 and the vdi opens about 5252 rpms...



check for a clogged cat, the split air pipe, your aux port actuators...



quick edit... i dont know if the s4's have VDI, i dont think so...

thanks, will try/check