Missing 1998 K1500 5.7L

[Mancyzr900]

This is driving me crazy. I have a miss/shutter on the top of big hills. I do not get it any other time and it is only when I lift off the gas and it shifts back into overdrive then step on the gas. It will shutters like it is getting to much gas or not enough. It only lasts for a couple of seconds, then clears up. If I step on it, it goes away. I have replaced the cap, rotor, spark plugs, wires, air filter, gas filter and cleaned the area around the fuel injection block. I did get a misfire code on the #4 cylinder a couple of times, but I tried switching wires, plugs and driving with the code reader hooked up, but nothing worked. I did get a catalytic out of range about a month ago. I am thinking it might be that, but if I rail on it and get it up to 90, let off and pick it back up at 65, it does not miss . Do not know anyne with a scanner without paying $80/hour. Any ideas??????

[maxwedge]

An intermittent misfire can cause the cat code, the 80 an hour isn't the issue here, what is, is if the condition is not consitent , they may not find it, make sure all you wires are on right at both ends, make sure you didn't crack a plug. If it feels like a stutter misfire only in lock up under a load, it could be a lean misfire but that would normally set a different code. You could check the fuel pressure under load if possible to eliminate that possibility.

[asguti]

seems like this is a common occurance with the K1500.. this is happening to my Suburban as well and I getting a missfire/dead cylinder code on #4 also, I was trying to research on-line and found several threads describing the same issue with #4 cylinder

[maxwedge]

Please look at the age of the posts before replying, way too old!