Hello, i am new to this site, and have a funny problem with my 96z28/ssclone car that has me stumped. When driving at any given time it will act as if it wont take the gas and almost stall every time you try to give it gas, all at the same time i notice the ABS & Traction control lights come on nearly all the time when this happens. And sometimes if i am not mistaken, that it does same thing without them lights coming on(rarely). So i can drive for days and it runs like a champ, and when you least expect it, there it goes wanting to stall on me when i give it gas going down the road, or taking off from a red light.

Ran fuel pressure test holding 46-43 psi solid, so that cannot be the problem.

Parts listed below replaced since i bought it 2 years ago.

Map sensor, Oxygen sensor, Throttle position sensor, Mass air flow sensor, Temperature sending & receiving sensor's, Oil pressure sensor, Accel performance coil, Oem distributor, Fuel filter.

motor has also been rebuilt with new bearings & drive entrainement impulsor. Found out who ever had my car before, swopped an 95 LT1 block instead of an 96 block witch i do not think makes much of A difference. Car has 103k miles.

I thank anyone for taking time to read through my problem, any ideas on what to do next would be appreciated.

 

Do u have a service engine light on d scan it to at least see whats going on

 

Maybe the wheel sensors are dirty or the connections need to be reseated. Possible for the traction control to drop out the gas when it thinks tires are slipping?

 

Only codes it gave was leanbank2 and miss fire. and i do not know how because it never back fires it runs great. Only when it acts like it wants to stall at most random times, and even then it never backfires at any point, so i do not understand why these codes are showing.

 

Why didn't you replace the spark plugs and wires????

 

A misfire is not necessarily a "backfire".... it's a stumble. Did you get P0300 for "random misfire", or was it a cylinder-specific code? When it "act(s) as if it wont take the gas and almost stall(s) every time you try to give it gas,", it's probably misfiring.

If you got a code for bank 2 running lean (was it P0174 - bank 2 fuel trim system lean?) it means the long term fuel corrections on bank 2 (passenger side) are having to add more than 22% extra fuel to keep the engine from actually running lean. Could be a problem with an exhaust leak before the O2 sensor, excessive misfires on that bank, a plugged injector, a vacuum leak that only affects that bank of the engine, or a faulty O2 sensor.

I would scan it and get the long term fuel trims for BOTH banks. You may have a problem that is affecting both banks of the engine and Bank 1 may be close to setting the same lean code (P0171), and just below a +22% average fuel correction.

The fact that the poor performance seems to synch with the ABS INOP and ASR OFF lights activating may be pointing to a poor ground somewhere in the system.

Under what conditions did you measure fuel pressure range of 46-43psi? At idle, with the vacuum compensation line off the fuel pressure regulator (FPR) you want 43.5psi, with GM accepting anything in the range of 41-47psi. Reconnect the vacuum line to the FPR and the fuel pressure should drop to about 8psi below the "no vacuum" pressure. So you would be looking at something in the mid to high 30's. With the car out on the road, max engine load (over 5,000rpm/WOT) the fuel pressure should not drop below 40psi.

Just curious - what's a " drive entrainement impulsor"?

 

Problem solved. XD Turned out to be the crankshaft sensor and very easy to replace.

 

I would expect the problem to come back. The crank sensor on the LTX was there to detect misfires only. It does not affect engine performance, it just causes a trouble code if the crank speed does not match what is expected. To prove it unplug the sensor and run the engine. It will set a code, but the engine will run the same.

The opti low and high resolution pulses are what the PCM uses to run the engine, both for injector pulse and for spark timing control.