swift700

iTrader: (3)

The spark plug was black from before the exhaust pipe changes. Also, I hadn't run it hard in a while to see my boost was just before the swap. Plus, it had been running slightly rough and using more fuel for a little while. I will do a compression test tomorrow. It has new plugs and wires. The lifters are quiet.

kelsey_canard

iTrader: (5)

What all was changed between the before measurement and after measurement? Besides exhaust of course.

swift700

iTrader: (3)

Bigger headers, y-pipe and exhaust, as well as plugs and wires. Oh, and the transmission. Put in another rebuilt one.

I'm going to compression test that cylinder and look at the valvesprings and rockers. It's an easy one, the right front cylinder.

swift700

iTrader: (3)

I noticed another thing. My fuel trims are mismatched. I have a theory: I'm running the Crane pedestal roller rocker setup and am thinking that the one cylinder's preload has come out of adjustment. If the preload is too light, the exhaust valve will open late and close early, resulting in an incomplete evacuation and added backpressure. It's like having a worn cam lobe.

Maybe I'm overthinking this lol.

Vortec350ss

iTrader: (20)

Did you ever get to the bottom of this?

Ferocity02

iTrader: (59)

Different fuel trims between banks is not uncommon. In mostly stock form I would see on average 4-5% difference between banks. I figured it was due mostly to the O2 sensors behaving slightly differently. Try swapping the sensors between banks. Also slightly different injector flow rates can cause it too.