A while back I did some research here and corrected a few problems with my 98 4.2L. After replacing the MAF my truck runs more smoothly. It no longer stalls as I brake to a stop or turn corners. However, I just read the new codes and am dealing with the following: p0141, p0156, p0161, p0171, p0174. Running lean Bank 1 and 2. The O2 Sensor Heater circuts are for Bank 2 Sensor 1 and Bank 2 sensor 2. I replaced the upline O2 Sensors about 2 months ago just before I replaced the MAF. I still have a bit of a rough idle and it sounds like the lifters want to rattle time to time when pulling uphill after the truck is nice and warm. My normal daily round trip is about 10 miles at about 35 mph. And I don't know if makes a differance but apparently I have one of the Canadian built engines according to the Engine Number. Any ideas would be greatly appreciated.


Malcolm

 

Start looking for vacuum leaks. The rattling is probably spark knock, not lifters. If the heater circuits are faulting on both sensors on the same bank, start looking for a wiring problem.

ALL 4.2's are Canadian-built - Essex is the only plant that built them.

 

check the PCV valves and hoses, i had a similar problem and there was a hole in the PCV hose. the hose on the driver side is easy to find but the hose on the passenger side is up against the firewall.

 

I know this an older post but I'll start asking here first. Just replaced the hose that conects underneath the plenum. I know I have a vacuum leak there somewhere, just having a difficult time finding it. The elbow that connects to the plenum seems to be metal...Is that true? If it's not, how does it come out so i can check it for damage? Any other ideas about another vaccum leak in the same area would be helpful.