Also think about cleaning your MAF.. Running oiled air filters is very common
for some of the oil to get onto the maf.. Clean it.
When was the last time you changed your upstream oxygen sensors????
They are pretty much a maint item anymore.. Good for 100-125K... They should
have been replaced at least once as reg maint since you have 250K. Get the good
ones: GM or ACdelco if possible. Just don't get the cheapo ones
Also would be a good idea to do a reset on fuel trims and ethanol % as mentioned.
The ethanol is calculated "virtually" on our rigs. So if oxygen sensors are crappy
you will get funky ethanol calculations
for some of the oil to get onto the maf.. Clean it.
When was the last time you changed your upstream oxygen sensors????
They are pretty much a maint item anymore.. Good for 100-125K... They should
have been replaced at least once as reg maint since you have 250K. Get the good
ones: GM or ACdelco if possible. Just don't get the cheapo ones
Also would be a good idea to do a reset on fuel trims and ethanol % as mentioned.
The ethanol is calculated "virtually" on our rigs. So if oxygen sensors are crappy
you will get funky ethanol calculations