Join Date: Jan 2003
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Re: what sensor to replace next
Try the Oxygen sensor. My truck was doing the same thing. Then I dropped in another engine and it was much worse. I assumed that there was something done during the swap that caused the problem. I also replaced most of the sensors and had 2 diagnostic computers hooked up and ran every test and they came out normal. I hadn't replaced the O2 sensor and didn't bother since the diagnostic said it was fine. My truck worked OK cold and then would start crapping out when warm and if idling it would quit when I popped it in gear. Watching graphs on the diagnostic computer, I could see that the computer in my truck would gradually retard the timing and richen the mixture until it stalled. Then everything would go back to normal when it was restarted and then it would richen and retard.
I called a friend that owns a shop back east and he said he ran into a similar problem. It was a Dodge and the owner had installed headers and dual exhaust a few years ago. He taped up the O2 sensor and strapped it to the frame rail since there was no place to put it. The truck ran fine for 4 years and he plowed snow with it every winter. Then the computer crapped out so he installed a new one and put the original exhaust manifolds back on, and stuck in the old O2 sensor. The truck ran exactly like mine, good cold, worse warm and then quit. A few guys had a crack at it but couldn't figure it out. Then my friend Pete replaced the O2 sensor and it was instantly cured. Well, almost instantly. He said he had to drive the truck for 1/2 hour until the computer relearned to run with the new sensor. He thinks the old computer bypassed the O2 sensor when it was disconnected and the new computer was taking bad info from it.
I removed mine 2 days ago and it looked like a lump of coal, even though the tests said it was working properly. Since it was shot anyway I tried to revive it. I scraped the crap from it with a knife and file, cleaned more with a wire brush, and then dug out the little openings with a needle. I popped it back in, went for a spin, and it worked much better. I bought a new one and installed it last night and now she's mint. Try it.