Yesterday I left the job site doing about 25 mph and when I started to slow down to stop and turn the truck started to run very rought and it was popping. It's been doing that in drive (gear) ever since....once I put it in N or P is comes out of it pretty fast and runs like nothing was wrong until I put it in gear. So I took it to the shop today and had the codes pulled and came up with a bad front o2 sensor. So I replaced it drove it same thing was happening. So I said screw it and bought the rear 02 sensor. It runs a lot better exept when I was coming to a stop it started to idel low and seem like it was loosing power. What could this be? Truck has abour 190,000 fuel pump wa replaced at 140,000 +/- rebuilt tranni at 179,000 +/-. The Iac and TPS or any other sensor other then the onces in the tranni both 02's have ever been replaced.
ALSO the check engine light isn't being tripped.
Thanks
Adam

 

Has your plenum been done? How is the cat?

 

Make sure to clear the codes & check the cat.

 

I havn't done the plenum yet.....I keep on looking into the throttle body for signs of oil ever 5,000 miles or so but never see any....(I've been told that you will see oil inside the plenum if it needs to be fixed.)

I unhooked the battery to shut the light CEL off. How do you check the cat??

 

By the way both of the old o2 sensors where not fouled.