KingsHustleLA

My 90 Iroc-Z has been giving me the same problem for the past 6 months, it lacks power, idles pretty shitty, and in stop & go traffic it starts stalling & dies out, it starts right back up sometimes but stalls out almost instantly. I have to let it sit for like 45+ minutes until i can start it up & drive it again then it repeats the process. I thought it was a bad O2 sensor & I replaced it a couple months ago but it died on me the other day & the check engine light flashed code 44 which i guess mainly means a bad O2 sensor and I read something about "lean exhaust". I took my car to my friend to hook it up to a scanner & it showed the O2 sensor was working. It's an after market O2 sensor i believe a Bosch, are they known to go bad almost a day or 2 after they're installed? Another thing can my fuel pressure regulator or EGR valve be bad and have something to do with causing the O2 sensor to detect lean exhaust & triggering code 44?

I really need help with this it's been months already and i've taken it to a few places and nobody can figure this bs out.

ninetyone

iTrader: (2)

sounds like you have a bad fuel injector http://www.youtube.com/watch?v=_g8PdrT0MCUrr.

ddd586

My 90 IROC 5.7 had the exact same problems and it was indeed the fuel injectors. 6 of them were perfect and two of them were very bad. You can easily OHM test them yourself with a multimeter. Search on here to find out how to do and also for what the OHM tolerance should be.

KingsHustleLA

Thanks for the replies. I tested the resistance on all 8 of my injectors and all of them had the same resistance and they are fairly new.

However I unplugged the hose that goes from my fuel pressure regulator to the plenum and it smelled like fuel. I left my car running and didn't see fuel come out of the regulator when I unplugged it but I noticed the idle immidiately went from rough to smooth and when I plugged the hose back onto the fuel pressure regulator the idle went rough and the car got a little shaky again. Would that mean the regulator is bad? I'm thinking it is. Also, would anybody happen to recommend a good adjustable fuel pressure regulator? So far I've seen TPIS, Accel, and bbk makes them for TPI's. The Accel is very pricey and the BBK and TPIS are only about $10 apart. Would one of those be good or is the Accel worth the money?

hotrodbrews

What type of injectors do you have? Hopefully not Accel. I've been chasing a similar problem on my 93 LT1 in my Hot Rod, it's the POS Accel injectors. Kept getting DTC 41, replaced Coil, ICM, start & die. Code 41 again. Checked resistance, good. Did the trouble tree for DTC41, everything checked. no opens or shorts anywhere. Brand new Dynaspark distributor. Pulled 4 random plugs, all wet. Checked with S&P in Mena, AR, they won't deal with Accel because of bad injectors. So new injectors, only this time Venom.