98 F150 STX 4.2 2wheel dr. ext.cab.Yesterday my check engine light came on. I cleared the code, and drove 40 miles hauling my small enclosed trailer. On the way home, just after leaving the parking lot the light came on again. When I got home I disconnected the battery, and left it that way overnight. Hooked it back up today, and the light stayed off. I drove the truck about 20 miles(no trailer) without incedent. On the way home, same thing. Just pulled out of the parking lot, and the light came on. I went to a buddies shop to have the truck scanned, and it read 02 sensor bank 1 and 2. I don't believe that both sensors went bad at the same time. Is there anything else I can look for?

 

lean or rich? im guessing lean.

most likely an intake leak or a plugged fuel filter/weak fuel pump

 

What are the exact codes? It's PROBABLY both banks rich or both banks lean - and the O2 sensors are doing their job fine!

If it's lean, 90% of the time its a rotten PCV elbow behind the throttle body.

 

I don't know what the exact codes were. He just said "o2 sensor bank 1 and 2" as he read the screen. The truck runs great, doesnt idle rough, no misses or anything. Then all of a sudden I will notice the cel is on. Even when the light is on the truck runs fine, but is obviously slower accelerating, and worse on fuel as it should be.

 

I hooked up the battery and started the truck up this morning. It was around 5 degrees celcius, or 40 farenheit. I warmed the truck up and it runs fine. No CEL, no stumbles, no misses, no surges, or flat spots when I rev it. Everything seems fine. The elbow that I could see looks fine, and the other hidden one felt fine. The times that the light seems to come on is after letting the truck sit for a couple of hours. The light doesn't come on when i start the truck. It comes on when I accelerate to traffic speed.

 

If the CEL comes on again, get the exact "P" codes, please.

 

I'll try! The lght never came on for a couple of days, then it came on again after dropping my buddy off. I reversed out of his driveway, and as soon as I put it into Drive, the light came on! If the truck didn't look so good I would have got out and kicked it!

 

Okay, now you can go read the codes - and we do need the exact "P" numbers, not an interpretation, please.

If your buddy's scanner can't do it, most auto parts stores will read them free.

 

I'm in Canada. I stopped into a NAPA store the other day, they couldn't help me, and knew of no other stores that could either. Canadian Tire wants 80 bucks to do a scan! or should I say scam?

 

Autozone and Advance do it free down here everywhere except in California. In California, you buy the scanner, scan it yourself in the parking lot, then return the scanner, no restocking fee.

 

!!!!!!!! LOL!!!!!!! THat's good!!!

 

I dunno what it is about California, but it's not just parts stores. Last Christmas, my sister and I went to Best Buy to get a bigscreen TV. They offered to help us get it to the truck, but they were not allowed to cross the red line in front of the store into the parking lot. I had to go get the truck and pull it up to the curb, and my sister and I had to lift it off the cart up into the truck.

The Autozones have a scanner out of the package just for this, it's not like you are buying one and tearing it out of the package and then returning it. I bought a set of wiper blades from Autozone here in MO, they went out and installed them for me without even asking. When I took my sister's car to Autozone in CA to get wiper blades, they wouldn't install them even when I asked.

Oh well - nothing surprises me in that flaky state.

 

they're lucky ur so nice to that best buy. i would've been a complete a**hole and backed the truck throught the sliding doors. sorry for the off topic post. couldnt resist.

just out of curiosity, was it all on the same tank of gas?

 

I drove the truck about 180 miles between yesterday and today without a glitch. I stopped for a coffee and a leak, and when I started the truck back up it kind of hesitated right after it started ,then caught itself. I knew the light was going to come on, and it did as soon as I pulled out onto the road. I have also noticed this before, but today I was really aware of it. I pulled into a parking lot, and pulled the neg. cable off for about 15 minutes. I then drove the last 40 miles back home without a problem.

 

Why are you clearing the code? You need to find out what's going on instead of just "rebooting" the thing!