2015 Tahoe P0300 Misfire and StabiliTrak Light

Question

My truck started running extremely rough this morning while at a stoplight and the check engine light began flashing along with a 'Service StabiliTrak' message on the dash. It feels like a dead miss under load whenever I try to merge onto the highway. I can smell raw gasoline from the tailpipe after a short drive.

Jake Morrison · Accepted Answer

The issue turned out to be a failed Direct Injection fuel injector on Cylinder 1 that was stuck wide open. I confirmed this by checking the fuel rail pressure drop after key-off; it plummeted immediately. I replaced the cylinder 1 injector (Part #12668390) and the required one-time use high-pressure fuel crossover pipe. Total parts cost was about $240 and required pulling the intake manifold, but it solved the misfire and the StabiliTrak light immediately.

Pete Sanders · Answer

You should perform a relative compression test using a scan tool if possible. These Gen 5 engines are notorious for Active Fuel Management (AFM) lifter failures. If a lifter is stuck down, the valve won't open and you'll get a permanent P0300.

Sam Holloway · Answer

Since swapping the coil didn't move the misfire, you need to check the spark plug wires. These LT1/L83 engines have very short wires that are known to boot-leak or develop high resistance, causing a rhythmic arc to the manifold heat shield.

turbo_tony · Answer

Check your fuel trims. If the LTFT is pinned negative on that bank, you might have a leaking High Pressure Fuel Pump (HPFP) seal dumping fuel into the crankcase, though that usually affects the whole bank and not just one cylinder.

2015 Tahoe P0300 Misfire and StabiliTrak Light

Suggest a repair