Pip4681 Random Bump Chuggle Or Fishbite

[justlearning]

I have a 08 Sierra Denali and recently made a trip to the dealer for several non-related issue to this. However my truck has a engine miss that occurs at low rpm (1500 or under) under very light load (cruising uphill). The dealership said that this was normal for this motor and offered PIP4681 as proof. Is there anyway to cure this issue? I tried to do a search and found nothing on the subject. If you run the motor at any other rpm by manually downshifting or accelerating harder to force a downshift it goes away. Motor runs great otherwise.

[[email protected]]

I have a 08 Sierra Denali and recently made a trip to the dealer for several non-related issue to this. However my truck has a engine miss that occurs at low rpm (1500 or under) under very light load (cruising uphill). The dealership said that this was normal for this motor and offered PIP4681 as proof. Is there anyway to cure this issue? I tried to do a search and found nothing on the subject. If you run the motor at any other rpm by manually downshifting or accelerating harder to force a downshift it goes away. Motor runs great otherwise.

Many chevys do that if you leave them in overdrive when you try and pull a hill at about 55+ mph. You can run higher octane, if you don't like it, but it sounds perfectly fine to me also.

[justlearning]

I am running 93 octane every tank. Also this doesn't happen in overdrive. It can happen in all gears under light load acceleration.

[justlearning]

BTW. In you signature it says that you ran a 12.89 at 93.4. I assume that this is in your 2500?

[[email protected]]

BTW. In you signature it says that you ran a 12.89 at 93.4. I assume that this is in your 2500?

 

Yes, that was with a SC and a 150 shot, though. Also, a little weight reduction.

[[email protected]]

Is your truck not under warranty? It could be a bad coil, but that's really rare on a GM. Being an 08, I don't see what could be causing the pinging. Spark plugs, wires, o2 sensors maybe? Any codes?

[justlearning]

Its not pinging. It is more like a large camshaft in a little motor. It just randomly misses under light load and very little throttle input. I don't know if there is going to be a fix as there is not code or light on. It just misses until you run the motor up a touch more in rpm like cleaning it out. It doesn't pop down the exhaust or back thru intake or anything and is very slight but is noticeable to me and those who know motors and ride in truck.