Many thanks to you both. This is EXACTLY the type of reply that I wanted - and expected - from fellow Corvette enthusiasts. Who would have thought of switching the O-2 sensors? What a time and money saver . . .

I will try it and reply with the results.

Thanks again, Gary

I have a '95 coupe with 47K miles, auto. Last week it started stumbling and missing and idling very rough. I babied it home and noted very black soot on the rear bumber fascia and black soot coming out of the exahust (both sides.) I ran codes and "H-64" came up, translating to a "Lean oxygen sensor, left bank." I cleared the code and started the car and drove it around the block. Ran fine for a few minutes and then it repeated the problem. I again obtained codes and got the "H-64" again. OK.

The fella at AutoZone researched and found the factory original part number and asked: "Front or rear sensor, left or right?"

Front or rear . . . left or right???? I saw only one in the factory manual, and it was located on the exhaust header in front of the cat.

Anyways . . . a "lean" reading would not equate to black soot coming out of both pipes, right?

Before I open the Snap-On box and start turning wrenches, I thought I should check with the "gurus" here and get a few recommendations and maybe narrow this problem down.

The car ran great with absolutely no problems. . .up 'til now.

Any thoughts?

Thanks in advance, Gary

Case - thanks. My fault for not providing more information.

I was driving in normal traffic, outside temp was about 55 and dry. No water came near the Opti. Car started sputtering at a red light - interestingly enough after a rather quick and aggressive right hand turn. I nursed it home and the "check engine" light came on several times and then went out. There were no engine knocks or other bucking, etc. I noted heavy black sooty exhaust, and it covered the rear of the car.

Once home, I let the car set overnight and pulled codes the next day. I used the paperclip method on the 16-pin ALDL box by shorting #4 and #12. Readout on the DIC:

Module 1: C-12 (I know that this means OK)
Module 4: H-64
Module 9: Nothing
Module "A": H-24; H-61; H-62

I checked underhood for loose plug wires, vacuum breaks, dripping gas, etc., but found nothing. I started the car and let it idle for a minute then drove about ten miles with no problems.

I do not race or abuse my car, but I do open it up at times on straight roads or while passing, etc. This is the first time this car has acted up - only 47K miles. Some of the codes may not apply to the current condition. I have received replies from other threads, with no success with the "H-61" code.

In reading your reply, you note that H-61 in module "A" refers to the SIR. I also noted that my "Air Bag" light comes on and then goes away after a few seconds. Can this be it?

In any event, if NONE of the codes apply to the current situation, what could have caused this sputtering and intermittent "check engne" light, and THEN clear up?

Your thoughts? Thanks, Gary

[size=12:55924920c5]Hey kids - get those pencils ready, here's the QUIZ: Yes, I received a Code "H61" when I retrieved codes via the paperclip method. There is NOT a code 61 in ANY of my manuals, in any of the forum threads, or even in any of the "F" Body websites. Yes, I am sure of the number - even checked it twice (like Santa does his list). Does anyone have a clue?

Prior to struggling back to the garage, heavy black soot was coming out of the tailpipe and covering the entire rear of the car. I checked a few fittings and generally shined the flashlight around (like THAT was gonna help) . . . Now it runs fine.

C'mon guys/gals - someone has to know what's going on here . . . lol

Thanks in advance, Gary
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