I purchased a 1993 40 Anniversary ruby red corvette with 58k miles in 2022 and have been chasing a H-44 code (lean left bank) since then. I first replaced the o2 sensors with Bosh and then again with GM due to the problem not being solved. I then replaced just about every sensor in the vehicle over the last 4 years. Thinking it may be a vacuum leak checked all hoses and did an improvised smoke test. During this time the car ran well. This past month I was getting a stall after driving when or a stall when idling this is common with an Opti-Spark problem based on several forums. So I changed OPti -Spark ,water pump, spark plugs and wires. While I was waiting for the Petris Opti parts I decided I would change the upper intake gasket and completed that also. The car runs a lot better but am still getting the H-44 code. I cleared the computer several times. It appears as soon as the electric fans come on the SES light comes on. The engine temp is fine never runs above 190* or maybe 205* when hot outside in traffic. The SES light will go off at some point while cruising on the highway and come back on. There are going to be to answers on this forum, I guarantee I have completed many responses. I may just take the light out that illuminates the SES light. I'm thinking it may be a computer issue the black box near the fire wall with the 4 plugs going into it. I have also changed he ECM prom and the problem was still there. Throttle body has all new gaskets and was cleaned last year thinking maybe it was sucking air through the throttle body that had its original gaskets. I would like to solve the problem and know what it is vs taking the light out.

 

It appears you are closing in on whits end. Not knowing how the car acted with the previous owner and what was done about it makes you starting at square one. Or maybe that was revealed to you. You could be right about ECM issue, you could pull the ECM out and send it to a ECM repare shop for an evaluation. Just to eleminate that possibility. At this point it's a guess where the Gremlin could be. Are you sure you don't have a fuel/pressure or injector issue? Do you know what the A/f ratio is when the SES light comes on? There could be a possibility the ECM connections need to be cleaned and maybe tightened, also with the sensors, and look for loose or corroded grounds. Hopefuly it's a minor issure. I think you are on the right track. If you think its more of a fuel issue than electrical, you could weld a bung into the left side exhaust and hook up a temporary wide band gauge and o2 sensor to find out where the A/F is at.

 

I don't think you received my first reply I hate how these forum posts work. I sent the ECM to SAI electronics in IL about a year ago they said everything was fine with the ECM. I just checked the fuel pressure while running 46-48 lbs. The injectors were replaced with Accel 24 lbs injectors two years ago and the fuel pressure regulator was changed out with the original to a AC Delco and just recently to a Aeromotive Inc that is adjustable and obviously it set at the above pressure. The fuel filter was also replaced two years ago with an AC Delco. I don't know how to check for the A/F ratio and what is a wide band gauge? The problem with the 92-96 Lt-1 is nobody wants to work on them. My mechanic worked for Scuncio Chevrolet from 1971-1991 and will not touch this car and is adamant about not working on it. My problem could be an array of reasons the SES light is coming on with H-44 code. There is also no modern scanner for this OBD 1, there is a scanner that the GM provided back then but who has that today. I appreciate your help. I checked the f/p reading car was idling perfect and the fuel pressure was good.

 

Most carguy1965 does look familiar, but I don't remember the original thread, sorry. It looks like you have done all the obvious things you can do. Most obd1 scanners have been discontinued, but there are still a few out there. I did see a Actron CP9190 Elite Auto Scanner under $100 that scans obd1 and 2s, it has been discontinued but can be found. Not sure if that would answer your questions. I haven't used a scanner on the obd1 system. I have never known any mechanic that likes working on Corvettes, fun to drive but not to work on. They are low to the ground, compact and complicated. God help you if you smear any grease on anything. You could swap out the old ECM for a new one if you are at that point. I have replaced ECMs that checked good with a new one and fixed the problem. Bad contacts? I don't know. Someone said once they had a Bad PCV Valve causing a lean condition.