1999 ford explorer xlt 4.0 4x4

Question

Ok so I have been helping my little brother with his ride. Here are the codes
p0430
P0301
P0302
P0303
P0172
P0174
C1102
C1230
I know the c codes are an abs sensor

The p0300 codes are misfires. I had a compression check and its a little low. I bought from a good friend that I trust. He just went through the motor. New valves and all. Had a smoke test to check off vaccuum leaks. Have changed several sensors with no luck. While changing the downstream o2 sensors we thought we had it. Cleared code and started. No rough idle and it seemed ok. Then after a few miles it started running rough again. The dealer tellsnme that they think its a possible cracked cylinder head. Another mechanic says timing belt. What concerns me is that problem went away then came back. Mechanically when its done its done. Sensors maybe. Any ideas would be greatly appreciated

Thank you

Answer 1

if u had heads off could be open to short ..on ground ..i know it doesn't sound like mush but if some ground wires not hooked up ..computer will not function right and problem could be intermittent. .comes and goes rough idle. .could be that timing is off a tooth thats all it can take on timming looks on but isn't. .hope this might help u..

Comments

Thanks for the help. We ended up disconnecting o2 sensor and driving around. Ran horribly. Hooked it back up and it was fine for like 20 miles. Going up the hill back to house it started up again.  I was reading another post and decided to take kn filter out as well. Something about the oil on filter trips codes. So I went from 6 codes to 1 code now p1151. We are gonna change front o2 sensors and possibly maf sensor. Any other ideas would be helpful