2008 Tahoe STILL has misfire. Please send help

[PG01]

The fuse box... it’s in 2 halves take it apart and I guarantee it’s corroded and that was your problem the entire time. They are known for it. Stuck in the sand? As in beach sand with salty water?

 

[89Suburban]

Sub'd.

 

[Chloe Golmon]

Yup, we live near Galveston we go on the beach all the time.
Fuse box will here wednesday, I'll keep yall updated, thank you!

 

[Chloe Golmon]

This may be a stupid question, but since it wasn't mentioned I'll ask. Did you try swapping plug wires and coils around to see if the misfire moves? Have you done a compression test? I know it's a new engine, but that doesn't mean it wasn't built on a Friday at quitting time. Just sayin'.

The scanner we have doesn't tell us which cylinder is misfiring. When we got it ack from the dealership the note said cylinder 4 but our scanner is just showing a random misfire.

We have since replaced the fuse box, the throttle body sensor, and the accelerator pedal. We cleaned the air intake. Used 93 gas. Still a really rough idle. And almost no acceleration. We are going tomorrow to have the crankshaft relearned. Anything else we should have them look for while we have the computer??

 

[thompsoj22]

Geeze, Im having an anxiety attack just reading this thread! Proof that without accurate diagnosis money wont fix a computer controlled vehicle. When you were stuck in the sand was there excessive wheel hop? Or just smooth wheelspin? The good in your situation is that it has a consistant miss, Im guessing electrical connector fubar somewhere. Let it idle with the miss and start tweaking every connector that deals with the engine management, including the interior fuse panel, ignition harness under dash,bcm,pcm and every cm you can find. I ask about the wheel hop as that situation will fubar even solid state epoxy encased modules. The injectors/harness/coils were reinstalled on the new motor, you are certain the fuel pump/module and the other components are good?? As stated the tech2 is essential but you have to know how to use it and have values/comparisons to isolate problems. alldatadiy. This vehicle does not have cylinder deactivation correct?

 

[mang213]

Well, they may need cleaning but that usually wouldn't the source of the maladies you're experiencing. I would get hold of that Bosch scan tool and have a look, if its a bi-directional tool that can run tests and relearns and such, you'll quickly identify the problem. My Texas vacation keeps getting cancelled! Have no idea when or if we'll get out there now this year.

Bad excuse dude. I just got back from a two week trip down to Texas from Washington DC. Drove my Tahoe instead of flying. Get down there, the weather is great and the fish are biting if you like to go fishing.

@Chloe Golmon As for the misfire and electrical issues for your Tahoe, I had similar issues that I chased around for an entire year on my 2009 Silverado. Quick question. What kind of battery is in that truck? We need to know the brand and type of battery.

Sent from my SM-G960U using Tapatalk

 

[Meccanoble]

This may be a stupid question, but since it wasn't mentioned I'll ask. Did you try swapping plug wires and coils around to see if the misfire moves? Have you done a compression test? I know it's a new engine, but that doesn't mean it wasn't built on a Friday at quitting time. Just sayin'.

This group just helped me with a misfire. I was going to recommend the same. Swap wires or coils to see if the misfire follows the other cylinder you swapped with.