Last weekend, I replaced my catalytic converter and also eliminated the resonator. My cat was pretty plugged and immediately saw an increase in power and MPG. Since yesterday, I noticed that when accelerating, especially at WOT in 1st gear, the engine cuts out at certain points. It will accelerate, cut out for 1/4 second, accelerate again, cut out again, accelerate again and then shift into 2nd gear. It does it also at moderate acceleration but not as bad but I do notice it. Light acceleration might do it but is almost not noticeable. No codes coming up.
Some history:
efans (fan codes removed)
PCM4less tune
Replaced variable camshaft phaser 2 months ago (the one on the timing chain)
Cleaned TB and intake manifold at same time as phaser replacement
New GM CPAS 6 months ago
New plugs, fuel filter last July when engine was replaced
Some possibilities that are popping into my head:
bad gas causing knock and PCM is momentarily retarding the ignition (I do occasionally hear some ping on acceleration)
low fuel pressure (I've had this before on my 4.3L Jimmy but caused constant loss of power on acceleration)
PCM is having hard time with new found exhaust flow?
Borked PCM tune?
Reason I say a possible bad tune is because the truck always did this after the tune. Was more like a "blip" rather than an actual rpm drop. This blip disappeared right after I replaced the cat but now is back and worse.
Any insight would be appreciated.
Some history:
efans (fan codes removed)
PCM4less tune
Replaced variable camshaft phaser 2 months ago (the one on the timing chain)
Cleaned TB and intake manifold at same time as phaser replacement
New GM CPAS 6 months ago
New plugs, fuel filter last July when engine was replaced
Some possibilities that are popping into my head:
bad gas causing knock and PCM is momentarily retarding the ignition (I do occasionally hear some ping on acceleration)
low fuel pressure (I've had this before on my 4.3L Jimmy but caused constant loss of power on acceleration)
PCM is having hard time with new found exhaust flow?
Borked PCM tune?
Reason I say a possible bad tune is because the truck always did this after the tune. Was more like a "blip" rather than an actual rpm drop. This blip disappeared right after I replaced the cat but now is back and worse.
Any insight would be appreciated.