I need some help on this problem I am having now. I have a 92 camaro, with the 305 engine and tbi., automatic. . the past couple months, my car intermittently acts like it wants to cut out. you see this by it suddently idling rough (like its not getting much fuel) at idle whether in park or in gear. you may feel the bump (hesitate) while driving. seems when shifting gears it may trigger it too. or at least its seems like it. it does not do this all of the time. it is so intermittent, its driving me crazy and worrying I will be stranded somewhere. most everything has been replaced on the engine at some point. no engine codes, a few times the engine light came on and right back off when it acted up, but it did not throw any codes. only once did the engine line actually stayed on for a couple minutes while driving, and when i finally found a place i could pull over, of course the light went off and it did not store any engine codes.

the transmission was rebuilt in april of this year, and when i did that, I did a big tune up. new cap rotor, plugs, wires, fuel filter, air/breather filters, pcv valve. o2 sensor. fuel pump has does wierd thing the past 3 years and I replaced it in june. with a new fuel filter of course.

I hooked a pressure tester to my fuel line and it reads steady at 10-11 PSI. unfortunately, i was hoping it would act up while i have it connected and never seems to want to do this on demand. couple times though yesterday I checked it again and it acted like it was going to act up and I swear I heard a click somewhere, but the pressure gauge didnt change at all. its steady even when open throttle. and I left it connected while just driving up and down my long driveway and the pressure didnt change.

when i first got the car a few years ago, i was left stranded when the fuel pump would turn on but no fuel out of injectors. i dont remember how i found this out (looked it up somewhere then) but ended up being the ignition module in the distributor then. so I pulled the cap/rotor off. found the ignition module was burnt open so i replaced the whole distrubuter. did not solve my problem

i have noticed it acts a little rough until you hit a certain RPM and seems to smooth out although sometime its smooth all the way. timing it sent to 2 degrees and it doesnt fluctuate with the timing light

only once, and i just replaced the CTS. the car suddently was speeding up on its on and I literally had to hold the break down. it happened while driving and on a busy road I couldnt just pull over anywhere to turn it off but a few minutes later (and bearing missing running into cars with breaks fulled depressed) it stopped and went back to normal. only once it did this and it happened so surprisingly that i dont recall like the accelator being stuck down or anything. so i dont know if its something mechanical on my end or the problem.

i have replaced the TPS, IAC, Map sensor over the years. but i dont know. i dont want to start replacing every sensor. its more frustrating with no clear picture. and winter is almost here..

any suggestions, where to began? appreciate any help on this one.

oh, i do notice when its in idle and acting like its getting little fuel, if I pump th ebrakes a fuel time. it seems i can cause it to idle up and fix it. takes a few pumps though. i feel its just something reducing the amount of fuel from the injectors. .. injectors also have been replaced. egr valve has. but this has been at least a couple years.

 

Connect a scan tool, look at the data stream. "Codes" are helpful, but the data stream tells (almost) all.

In particular, I'd look at actual idle speed vs. commanded idle speed, IAC position and operation, coolant temperature, MAP sensor, O2 sensor voltage and cross-counts, and EGR operation. But check "everything" for anomalies.

 

Most likely it the ignition control module. Buy an AC Delco replacement. Not a parts store or name brand aftermarket piece, only an AC Delco. If not I'd say a ground at the back of the engine or the TBI injectors need rebuilt.