Tommy Edwards

Ok. Here's the whole story. This truck was handed down to me and had been taken pretty good care of. It was losing power going down the road after warm up and started running hot. so the truck being new to me and wanting a good start I hooked it up to a diagnostic computer and it spit out a lot of codes. I started with a tuneup including plugs, wires, distributor cap, rotor and coil. I replaced the catalytic converter and now throttle position sensor and fuel filter. I have fixed the coolant leaks and thoroughly flushed all the stop leak out of the radiator and motor. The problem that I am still having is at operating temperature the engine will stop responding to the throttle momentarily and then catch back up. The only codes I am getting now is 172 and 173. Any ideas out there? 1995 F150 with 302 engine. I can depress the throttle until it powers through the power loss.

Tommy Edwards

WOW! 6 days and no replies? I can run 80+ down the hwy and it'll never stumble. anything less and it intermittently and momentarily loses power.

memoniz

Look up information about the Throttle Position Sensor (TPS). See if any info on that is similar to your issue. It maybe starting to fail.

Sorry, just read your post and saw that you said you replaced it.

memoniz

I was looking up the codes and don't know what HEGO is. On further reading its the O2 sensors. The Haynes book is saying that the PCM monitors the O2 sensor and adjusts the mixture as you drive. Seeing how it's reading rich and lean, the PCM is constantly adjusting itself. When you are driving 80, it's pretty much past trying to run efficiently. The book also says when you throw those codes, it will run in the default open loop mode.
So maybe read up on the O2 sensor. If it has not been changed, you might want to do that.

Tommy Edwards

Very good. I will test and replace if necessary. Thanks for your help.

Tommy Edwards

tried cleaning O2 sensor overnight with no change. Bought new one (from amazon bosch $20) R/R runs perfectly! Thanks.