Lq9 4l80 swapped silverado unsolvable misfire
07-15-2024, 10:17 AM
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Lq9 4l80 swapped silverado unsolvable misfire Hey everyone, new to the forums. But ive got one heck of an issue thats got me stumped. I've got an 06 silverado 1500 that's lq9 and 4l80 swapped.
So here it is. Truck runs great at idle, driving around town, pulls hard no issues wide open. But probably 80% of the time in reverse it shudders, shakes the truck and will occasionally stall. Then cruising in 3rd or overdrive above 2500 rpm at constant throttle it will flash the engine light with a misfire code. Lay into the throttle it goes away, and under 2500 rpm there's no issue.
To eliminate the possible issues it's running a stock lq9 and 4l80 tune
all sensors were new ACdelco at the time of the swap
new delphi injectors/fuel pump
new ACdelco coil packs
Only aftermarket piece is a set of speed engineering long tube's
My gut Says Torque converter for the reverse issue but thats an expensive parts cannon. Im at the end of my knowledge here so any insight is helpfull!
So here it is. Truck runs great at idle, driving around town, pulls hard no issues wide open. But probably 80% of the time in reverse it shudders, shakes the truck and will occasionally stall. Then cruising in 3rd or overdrive above 2500 rpm at constant throttle it will flash the engine light with a misfire code. Lay into the throttle it goes away, and under 2500 rpm there's no issue.
To eliminate the possible issues it's running a stock lq9 and 4l80 tune
all sensors were new ACdelco at the time of the swap
new delphi injectors/fuel pump
new ACdelco coil packs
Only aftermarket piece is a set of speed engineering long tube's
My gut Says Torque converter for the reverse issue but thats an expensive parts cannon. Im at the end of my knowledge here so any insight is helpfull!
Last edited by MasonG; 07-15-2024 at 10:39 AM.
