Update: OK, it wasnt the alternator. Just changed the battery.

Rechecked all vacuum lines, fittings and hoses. Removed all the spark plugs, expecting to find at least one saturated in a gasoline/carbon soot. Nothing. All very lightly discolored from normal use. No carbon build up on any of them, despite the fact that the truck is clearly running on seven cylinders 95% of the time. They look to me to be about three months old. Funny, considering that they are about three months old.... If it is running so rich that you can smell fuel in the exhaust, shouldn't the plugs be black and sooty? Could the extra gasoline be "washing" away the evidence, as crazy as that sounds? Really, the plugs were almost tooooo clean. And still not a single damned Check engine light!

 

i had an instince like this once, the only way i found out it was the ecm is watching the throttle position sensor on a scanner, it was very erratic and sometimes didnt exist, now that was on a tbi car but the symptoms sound about the same, oh yeah NO CODES on the car, so your not the only one, but it might be time to dig a little deeper

 

Success! I knew the truck felt like it was running on only seven cylinders most of the time. And at work, we have laser equiped, infrared thermometers. I decided to fire it up, let it idle till it started missing, and then check the temp of the exhaust manifold ports as they come off the engine. Sure enough, everything was about 350-375 degrees except for the #2 which was 200-250. I shut it off, let it cool for 20 min, and repeated the routine. Same situation, same cylinder. So it wasnt moving around to different cylinders. So spark problem. I just removed the plugs so i know it wasnt that. Decided to replace cap, rotor and use one of my spare ig wires on that cylinder. Problem solved.

Dont know what it was for sure, but since the cap and rotor looked fine, and all the other cylinders worked fine, im guessing there was something wrong with the wire. It was only 3 mo old but what can else can i say. Have no idea why it would run fine for a minute then start messing up either. And the strong exhaust, was just the fuel from #2 cylinder being blown untouched out the tailpipe.
So thanks everbody, and remember; Just because a parts new, dont mean it aint broke! Now, on to my tranny issues......

 

Glad you fixed it!! I wish my problem were that simple!

 

I hate coming on here trying to find a simple fix. Mostly because everyone over complicates these ****ing motors. There’s not that much to the electrical you don’t need to test everything. And the ignition modules aren’t that ****ing bad that every time there’s an issue with your truck you have to check them. What are the three things that keeps a motor running? That’s all you need to remember. If it’s running rich I would check your left and right side banks if your spark plugs look funny on the left check your left injector if your spark plugs look funky on the right check your right injector. If injectors are good check your map sensor. If your sensors good check your fuel regulatorThere are many more simpler ways to do **** they want these ****ers try to tell you

 

Nice 1st post Tyler! Ranting & ****''s on an over 10 year old post makes a great 1st impression.

 

i’m not out here trying to make a good first impression I just have a 94 that I get super frustrated with and it’s super hard to find the solution to a problem when they’re 16 different people on here saying 20 different things I just want to solid answers like from start to finish just wanna know what you did how you figured out that’s all I wanna know I don’t want to know where I need to put a voltmeter on 20 different things I don’t wanna know this I wanna know that I just want to simple freaking fix this is my first Chevy to know I’m a Toyota guy so my frustration levels were a little too high this morningAnd I apologize to anyone that that offends but anyone who’s worked on a vehicle knows how that goes So again sorry and carry-on

 

easy there sparky. i do understand the whole issue about everyone saying "i had the same problem and you need to replace XXXX". im more of a type of guy that whats to replace the right part instead of throwing parts that could be the issue. but like redneck stated theres no need in getting upset over a 10 year old post . if you have an issue make your own post and youll prob get help, but ranting on this old post wont solve anything. tell you the truth those that really help on here are dont get paid, so when someone come in with a tude they do tend to be ignored. so while youre not here to make a good first impression it may be in your best interest if you want help. other wise welcome from maryland

 

i have a 91 GMC Topkick with a 427 that loses power when it gets hot, shut it off for a minute and it has power for another half hour or so, anybody have a suggestion on what might be going on? thanks.