Ok, so I brought home another rescue and the misfire problem has me a little stumped so far - have not seen this before. Truck is a 2000 with SAI - 230k on the clock, recent headgaskets, intake gaskets, and valve cover gaskets by PO

Symptoms:

1. Misfire codes on cyl 1,3,5,7
2. Pops back through the intake at idle
3. Drives relatively well under power
4. O2 sensors show full lean condition shortly after startup. Cold start shows voltage in middle of the range and then steadily moves down to full lean.
Swapped in a known good sensor on bank 1(ds) and it shows full lean also.
5. Lean code on bank 2

Things tried so far:

1. Swapped O2 sensor (see above)
2. Swapped known good MAF
3. PO put on new coil wires and new plugs. I have doublechecked wire arrangement and it is correct.

Likely next step will be checking fuel pressure, then checking ds fuel line for a kink that could restrict flow. I might even throw my wideband 02 in the pipe and see what the actual AFR is on startup and warmed up.

Any ideas, please post them up. I will update the thread with what I find.

 

Since you have mis-fires on 1,3,5,7 I'd lean more towards a bad coil pack on that bank or a problem with the coil wiring itself. On that bank the wire lead to the coil is pretty short. It could have gotten pinched or knicked.

You can get coil packs for as little as 45.00 on Rock Auto.

 

I'm pretty sure its not the coil packs, because one pack fires 1,4,6, &7; and the other fires 2,3, 5,8. So neither pack controls just the left bank. Not only that, but due to the Rovers siamese coil configuration, 1&6 and paired on one lead wire with 4&7 on the other; similar on the other side, where if were a lead wire damaged I would expect misfires on the even bank paired cylinders. That's what my other one is doing right now (dead cylinders 1&6 due to bad coil pack).

 

I lean toward it being an O2 sensor problem, despite the fact you swapped it out for a known good one. Every time I've had problems with all the cylinders on one side it's been an O2 problem. Disco Mike used to swear a bad O2 couldn't cause misfires but it happened to me three years ago in May '14.

I chased an O2 problem last fall that drove me nuts. I didn't have misfires, but brand new sensors failed very quickly after being installed and I had P0130 and P0150 codes.

I turned to bench testing them with a propane torch and a multimeter. It was wacky. One sensor that wasn't working magically started working a few days later.

If you bench test or otherwise confirm good sensor(s) perhaps it's a defect in the harness. Try carefully checking the harness-side connector visually and maybe test continuity back to the ECM.

I personally doubt it's a coil since the odd cylinders are not all on the same coil.

 

True they're not on the same coil packs but 230K = for $40.00 I'd replace them.

 

Surprisingly enough, it turned out to be the injector o-rings. The po had pulled them out but not replaced them. Replaced them and all is good.