Hello...My 1999 WJ 4.0 l6 can't start. It backfires through the throttle body when turning the engine over. Initially it showed these fault codes: P0340, P1765, P1391, P0531, P0761 and C214C, some codes disappeared except for P1391 and later P0301.
The day it died, I filled the Grand Cherokee with gas to the brim, as I was making a long trip. That's when all hell broke lose. The engine had no power and was running as if it was cutting off fuel (pulsating), and it also increased fuel consumption significantly. By sheer luck i arrived at my destination.
I also recall that the MIL light flashed for some time while en-route.The next day it started fine, though it idled roughly, especially in reverse gear. It finally died as we were running the engine to read live data with a scanner. We cleaned the injectors (not sure if it was properly done), and it became worse. I bought a set of upgraded (4 hole) Bosch fuel injectors, changed CPK and camshaft sensor, no difference. Can you please help me troubleshoot the problem?
Presently the codes which are persistent when cranking are P0761 and C214C. I tried the quick start spray trick with no success. I have read threads about catalytic converter and camshaft target wheel. Can one of them or both cause it to backfire through the throttle body? Please help. I'm at my wit's end with this car.