Need some troubleshooting help

**98-LS1** · 08-03-2006, 05:08 AM

I just installed new vette Bosch O2 sensors in my Z-28 last night, the code went away but now the car stumbles and want's to die. Before it was running really rich but ran fairly well considering the O2's weren't reading correctly, now it's acting like it's getting either too much fuel or not enough. Last night at the Sonic it stumbled and started missing really bad so I had to feather the gas to keep it running, once it straightened out I opened it up to burn all the fuel off and it ran great after that. This morning it decided to do the same thing again. I ran the codes at autozone and it said I was getting a mass air frequency low and high. Would that cause it to stumble and run like crap? On top of this my A/C compressor took a shit on me last night, thought the motor blew up the way it was sounding. I heard this loud knocking sound after I left the Sonic, luckily it was just the compressor bearing going bad.

It's always something! Any thoughts on what to look for would be great. I'm going to clean the mass air sensor again tonight with some electrical cleaner to see if that helps.

**98-LS1** · 08-03-2006, 08:01 AM

well I noticed today while messing with the A/C that the motor only stumbles when the air is on but runs fine with it off. Isn't there a solenoid that controls the idle while the A/C is on? I'm thinking that maybe part of the problem, another thing the compressor would make all kind of racket then stop and be smooth and quiet for a while then act up for a minute then quit again. It's blowing ice cold air the whole time. Guess the compressor is on it's last leg but I can't figure out why it causes the motor to stumble and choke up every once in a while.

**0rion** · 08-03-2006, 11:34 PM

Could it be bearing noise you're hearing and does it make the noise with the ac off? I wonder if your bearings are shot and putting extra load on the engine. Just a guess but seems feasible.

**98-LS1** · 08-04-2006, 03:45 AM

I'm guessing that's what it is too, yesterday evening I messed with it a little and it quite blowing cold air alltogether now. I'm getting a new compressor today because this 100 degree weather is killing me, ain't no way I can live without A/C!

**mrr23** · 08-04-2006, 11:11 AM

more than likely, the bearings are freezing up in the AC compressor. which would be why it's stumbling and trying to cut out on you. the PCM controls the AC system. it's the ground wire for it. if the PCM reads too much voltage, it will shut off the compressor. once you have replaced the compressor, you may need to go into the PCM and clear the code for the AC. it will not trip a SES light. did this on my 94 LT1 years ago. took us over an hour to figure out it was the code in the PCM.