Hello all, I'm a novice with HPTuners/tuning and hoping someone might be able to spot an inconsistency that'll get me running.
Vehicle:
- This is a 2003 Suburban L59 (Flex Fuel 5.3) that I bought knowing it barely ran. Hoping to fix & use the powertrain in a buggy (100% off road use).
- It's got ~195k on the chassis & motor. Transmission was rebuilt ~12k miles ago.
- It is stock except for an intake and removed cats. Previous owner was concerned about clogged cats so I removed them, welded in test pipes, and disabled the secondary O2 sensors (one cat was about 50% gone).
- It was throwing a MIL for the fuel composition sensor, but nothing else. I disabled reporting for that but the sensor is still in line.
- I replaced the fuel filter.
- I replaced the MAF upon inspection finding a cooked resistor. Reset ECM and no change.
- *UPDATE 13 AUG* Replaced plugs & wires with OE spec Denso parts. Also did updated intake manifold gaskets per GM TSB. No operational change.
Current Issue:
- Recently, I've disabled the Flex Fuel (toggle switch in HPTuners), and changed the AFR to 14.68 across the board as another thread recommended.
- It starts fine every time, but will slow idle as it warms up, then starts to chug, and will eventually die.
- Responds roughly to throttle blips. With aggressive throttle stabs it will occasionally throw a 'random misfire' code (blinking MIL).
- Can move under its own power but runs weak.
I've got the tune file and 2 log files attached; the first was startup and warmup, the 2nd was as it started chugging and I had to blip the throttle to keep it alive.
I appreciate anyone's time who has the ability to help. Thanks.