hassgrant

I have a 91 Z28 305 TPI. I have been fighting an acceleration issue for awhile. First I thought it was the EGR system, but everything checks out fine (although I will throw code occassionally when cruising, but I have a solenoid off of a 91 305 Caprice). I decided to check the O2 sensor and found that I am not getting any reading from the O2 sensor or the O2 sensor connector from the ECM on my voltmeter. I mean, nothing, zilch, zero. I made sure I had a good ground for the voltmeter and made sure the voltmeter was working. The other thing I find weird is that I am not throwing any codes for the O2 sensor. I just replaced the ECM but I did not replace the prom. So is it as simple as a bad O2 sensor, which is only about a month old, or is it my O2 sensor connection? Any help is greatly appreciated. Thank you!

P-ROC

iTrader: (2)

Usually the output range of an O2 sensor is only .2 to .7 volts. If you try to test resistance with a voltmeter you will probably ruin it. Hard to detect that reading with a low quality testor.

hassgrant

If the O2 sensor is ruined, shouldn't it throw code? Just seems weird that if the O2 sensor wasn't giving any reading it should give code. I do know that the car runs great in open loop but has a fall-off in acceleration once it enters closed loop. In open loop, throttle response is great, but there is a weird, hesitation between hard throttle and throttle response in closed loop. It almost as if the car is taking a gulp of air or if the car is slow to respond to the hard throttle. It is a problem I have been chasing for couple of months now. Thought I had it down to wrong EGR Valve, but changed out an no change. Perhaps now it is an O2 sensor issue. These types of problems drive me crazy, LOL!