Question: I just replaced the motor in my 97 Ford Explorer v6 SOHC and had to put the old motor wire harness on it (the one on the new motor didn't start with the key and the transmission didn't work i dove it about 15 miles to a transmission shop and back
manually it ran bad to see if it was the transmission, it wasn't it was the motor wire harness. It starts up but after it warms up it runs really rough. I hooked it up to a computer and it said the 02 sensors were bad. I took them out and cleaned them and replaced only one (cause it was beat up looking).
Any ways the motor runs like crap when you put it in reverse and idles down and shakes bad. There is all kinds of pinging noises when i put it in drive i have my foot all the way down and it doesn't have the get up and go. It just struggles to pick up speed and goes to around 4500 to 5000 RPM before shifting out of 1st gear. The other gears are not as bad but still not good. I have spent too much money on it and need to know if getting new 02 sensors will fix this problem. Please help. Thanks.
Answer: Since I don't know if you put the same year engine in your Ford Explorer truck, it would be hard to say if this was just a wiring harness problem or something more. Oxygen sensor codes have a lot to do with how an engine runs no matter what kind of car or truck it is. Most of your problems could be related to bad oxygen sensors. Removing and cleaning oxygen sensors Make them worse. Again, I don't know if this engine that you put in was the same exact year.
You say that when you put in reverse it runs bad, idles down and shakes. This sounds like a loose ground or other sensor connector problem. But if it runs bad and shifts bad all the time even in drive, then this could also be just a fuel pressure problem. With the new engine and an original wiring harness you never know, just because a connector will plug in to the sensors does not mean that the wire colors and circuits are all the same. I would suggest replacing the oxygen sensors that have the codes, and check fuel pressure.
Comment: Check to make sure the spark plugs wires are on correctly. You may have a few crossed, especially if the new engine is not the same firing order as the original. Crossed plug wires will cause all kinds of running problem on your Ford or any car. The spark is getting to wrong cylinder and will cause terrible running and spark knock or ping.