[svandamme]

well, you could just have a look why first, if it has ODB2 . .. at least have a look at the short and long trim states.. it will tell you what the computer does to compensate.

V8 .. 2 banks.. all it needs is one faulting o2 sensor on one side and yer engine will run out of whack..


but you need to be sure of the spark first. That sets it all off and is primary
o2 sensors

I would think external titbits are more likely the culprit then internal wear at his mileage..
IF all the tidbits checkout and it still runs rough ,you'de almost have to see it with a compression/leak test , but that's really last thing to look for.