Andys89

I drove my 89 Vette around all day and drove fine, stopped for an hour started it up an began misfiring, running at 600-700 RPM up and down and a strong rich gas odor. What could it be?

65Z01

Stick a paper clip into ALDL pins A&B (upper right) turn the ignition on and count the SES flashes; come back with any error codes.

It could be any number of things but reminds me of the symptoms of my failed MAF.

Andys89

I get the feeling your right about the MAF, I forgot to say the air conditioning was on all day when I started the car the control unit was flashing on and off, is that the code?

65Z01

No, when you jumper the ALDL as suggested you will see the SES flash codes.

However the HVAC system does store trouble codes, though I don't know how to retrieve them.

Andys89

Well, I checked the diagnostic codes and only came up with code 12 and nothing else. The air conditioner is not flashing anymore but the car is still running ruff,could it be a bad plug?

Andys89

Pulled a code 10 on HVAC what does it mean?

65Z01

Sorry but my '88 Shop Manual doesn't list a HVAC code 10.

That's a good idea to pull the plugs to see if there is a problem with a cylinder; I would start with the right side since the O2 sensor is in the left side Y-pipe.

ojaijim

Check your hoses see if one leaks.

Rotten gas maybe ?

Bad injector ?

Midnite 88

It means that the fan is on max speed.

Just as a test of the "MAF" try disconnecting it while the engine is off. Then start the engine and see if it runs better. If it does, then you have a problem with the MAF or MAF relays. If it doesn't, then it hasn't cost you anything and you can do some more detective work.

Feel free to contact me for additional help if needed.

Mike.

Andys89

I am going to try testing MAF, Yesterday I changed the plugs and I noticed that the right side plugs were black the left side was normal brown. The car ran good the first 1/2 hour, then started to act up again after I put the new plugs in

msslp04

I had the same problem with the smell of running rich and stalling out when idle. It never gave a code except for 12. It ended up being the ECM. Check this thread I started.

http://forums.corvetteforum.com/show...48&forum_id=82

Kevin

Andys89

Thanks for the tip, i checked out the MAF and it runs no different, still running rich! I think the ECM is not regulating the fuel, so I guess I'll get one and see what happens.

kopbet89c4

If this an occasional/intermittent misfire or dead cylinder? Check and see if the spark plugs, spark plug wires and injector clips are on tight. Check to see if there is a short in your HEI coil right on top of your distributer cap. Once I did this, it seemed to have solved my problems! Good luck!

Andys89

I'll check that too, seems that the right side of the engine is getting to much fuel,a constant misfire.