I have a "96" GMC Sierra 1500. It has a 350 with an automatic. It has 215K miles on it. Runs great, has had the oil changed every 3,000 miles and doesn't burn a drop. I have to add a qt at about 2,000 miles between changes. I have for about the last month and a half been having trouble with my check engine light staying on. When it had been on for about a month. I found a bad 0-2 sensor in the exhaust and changed it. Then reset it and it went out. I drove it about 400 miles with no problem so I took it to get inspected. It failed and the light came on again while they had it on the scope. The scope showed that I had a misfire in cyl 4. So I changed the plugs, cap and rotor. Reset the light and drove it another 200 miles and now the light has come on again and now it won't even reset. I have had the negative cable off the battery for a half hour and when I hook it back up and start the truck on comes the light. I thought that the computer should have to wait up to 80 miles to register any codes to turn the light back on. Does anyone have any idea what may be causing this to happen? HELP!!!!!!

hadude
if your lite is coming on immediately it has to be a hard failure for it to set that quickly.If you have time to come to Mesquite sunday afternoon i will bring my tech2 home and i would be glad to look at it for you.call me on my cell
saturday around noon and we can set it up.
later
Stan B.

Stan,
I appreciate the offer. If I keep having trouble with it I will call. I disconnected the battery again last night and left the cable off for an hour. When I hooked it back up the light stayed off. I drove the truck out to my daughters in Grand Saline today for my grandsons birthday party. I put over 100 miles on it and the light stayed off. I hope that I have no more problem with it. If I do I will call. How can I contact you?
Thanks, HD

hadude 214-538-9071 cell

For the cylinder misfire you said you changed the plugs, cap & rotor. How about the plug wire??

Stan,
I can't tell you how much I appreciate your offer. I got my truck inspected today and it passed with flying colors. I don't know why the computer didn't want to reset. I have had trouble with the light coming on from time to time in cold damp weather. If I have anymore problems I will call.
On the other hand if there is anything I can do to help you let me know. I have been a carpenter and home builder for 30 years. There isn't much around a home or building that I haven't done.
Once again - Thanks,
HD

Adkins Angler,
Thanks for your post. I did check the resistance with my ohm meter and compare the wire on the bad cyl to the others. It was consistant. The truck idles better than it has in a long time. I think it was just the worn plugs and a rotor and cap that had gone 215k.
Thanks,
HD

Stan,
Today the "idiot light" came on again today. I had just looked and it was off. Calculated the mileage again and I was just over 300 miles with no problem. Looked at the dash again about 15 seconds later and the light was on again. Could I take you up on the offer to put a machine on it and read what could be happening. I have to come into Mesq Saturday sometime to take my Mother-in-law a cabinet drawer that I fixed for her kitchen. Let me know if there is a good time and I will call and set it up with you.
HD

hadude
i am sorry i will not be here saturday.my wife has a booth at Canton and i will be down there helping her out.I will probably be back in mesquite sunday afternoon after 5:00 pm if you want to set it up for then just call me.

I'll call and we can work out a time. I am not going to bother you on Sunday after you have been in Canton all weekend. I have my truck inspected so I don't have to worry about getting a ticket anymore. I work in Dallas and drive through Mesq. every evening around 6:00. Daylight savings starts this weekend. Maybe we can look at it some evening. I'll call,
HD

That will work.thanks