i have read some of the threads that are on here with similar problems. i did everything mafs,checked spark, change fuel filter andchecked for boost leaks. at idle she still bucks and chugs and stalls out. most of the time there is no throttle response at all. but when there is and i rev it to say 4000rpm if i let go of the gas it stalls out if i keep the gas peddle going abit in pluses it wont stall out but goes back to running like ass. It also runs rich sometimes and runs lean i dont get it? The damn thing seems to run fine when its warmed up. i think it might be the engine temp sensor? i know the thremostate needs to be changed becuase the temp is way off. if anyone has any insight on what may be causing this pain in the ass please share your ideas.
Check your fuel regulator vaccum hose/fuel regulator for problems. Also check for clogged injectors. Check your ecu and see what error codes it is throwing out. If it bogs and dies a lot, maybe one cylinder is lacking compression? Check gapping on the spark plugs and maf sensor. I had a problem similar to this today. I was boosting hard and then all of a sudden it just completely cut out, id press the gas and the rpm would increase like 300 rpm only, even if the pedal was to the floor. I shut it off and it ran fine. It then started to do this again, and I noticed when I went over bumps it would cut and die and I would have no throttle response. Basically what im getting to is that the maf is prolly causing this (i will check this tomorrow). I guess the maf or something else is coming loose when i go over bunps.
Check your injectors and your fuel rail!
timing, too.
definatly check fuel and timing,
it isnt your vac lines or fpr line.
i have my Z in the garage right now for that issue…
my problem is rough idle on cold starts, and stalling when the car is still cold (if i don`t keep my foot on the gas, keep revs at 1k +)…
apparently the lifter(s) on one or more cylinder may be dry, and takes a while to lube up…which i think is a line being fed to me…
this is a no brainer…but change your oil… sometimes that helps enough to problem solve some more…