can anyone tell me where the air temp sensor is on a 5.0? 1989 is the vintage.

also, i tried getting my oxygen sensor out and it seems to be free spinning in the hole. don't really know what to do now other then cut it off and drill it out.

anyone know why bosch says the change interval is 60,000 miles on the o2 sensor?

 

ACT (Air Charge Temperature) sensor is in the lower intake plenum between fuel injectors 5 and 6 near the front of the engine.

Has the bung for the sensor broken loose from the exhaust pipe? Its rare but it can happen. The sensor replacement interval is based on the useful life of the materials (particularly the metal alloy in the sensor body). In truth the 60,000 mile interval is a bit long especially if the truck sees harsh use, dusty environments or the engine has operating issues that cause rich running or warmer-than-normal operating temperatures.

This is the part where ol' greystreak talks too much...

The entire sensor is made of a metal alloy that reacts to the presence of oxygen. The alloy must reach about 300 degrees Fahrenheit before it will generate an electrical impulse. Yep, that's why the first O2 sensors did not get any power. And the newer HEGO (Heated Exhaust Gas Oxygen) sensors are fed power ONLY to pre-heat them so their sensitivity to oxygen is more accurate while the engine/exhaust system is still cold. The other point to make is that the BODY of the sensor is JUST as critical to its effective operation as the tip that is inside the exhaust pipe. The unit sends information about not one but TWO oxygen levels but it sends it as a small electrical impulse. The difference between the oxygen level inside and outside the exhaust pipe determines the impulse sent to the ECM. This is why an O2 sensor that sees a lot of poor engine performance or a lot of crud slung at it from under the truck will lose efficacy faster than one that does not. Want proof? Let a plastic garbage bag that is floating down the roadway get caught and melt to the body of the sensor and watch your fuel mileage go to hell in a handbag.

 

the oxygen sensor has probably not been changed in a very long time (judging by how tight the sensor was in the port hole)

i put a 22mm box end wrench on the sensor and pulled my weight towards it using my foot to push the wrench. i did that a few times and realized the sensor was not backing out of the hole at all. just turning.

also i had the o2 sensor unplugged with the truck running for about 20 minutes and the check engine light never turned on. i think it should have but maybe not. don't really know for sure.

dad was baffled that it only utilizes 1 sensor on the exhaust. almost makes no sense even having cats on the exhaust other then back pressure

 

EEC-IV didn't need more than one O2 sensor. It did its part to control emissions but actually served more to keep the optimal fuel-air mixture by tracking oxygen levels in the exhaust. O2 sensors downstream of the cats don't do anything but tell the computer whether the cat is getting enough oxygen to get the job done. In truth, the ONE upstream of the cat in the Y-pipe gives the computer enough info to know whether the levels in the exhaust going to the cat are adequate to let the cat get the job done.

The additional O2 sensors are redundancies so the computer can double-check things. They don't do anything more than that. The only reason for more than two sensors would be in the case of dual exhaust and/or if Ford had decided to put one in each arm of the Y-pipe instead of the convergence point in the Y. Gotta read ALL the exhaust for accuracy so its either down at the convergence or one in each arm. Less expensive to use one. The Fed told Ford and everyone else they HAD to use OBD-II in 1996. So we got cars with as many as four O2 sensors and in some cases more. expensive redundancy... but then that describes the Fed pretty well no matter what the topic.

 

could the o2 sensor be the real problem why i have super bad gas mileage if everything else that was making it run like crap has been fixed?

the video i posed on here not too long ago of my random *** check engine light was caused the the sensor on top of the EGR. i replaced the sensor and have not seen the light since.

gonna make a new vacuum canister this weekend as i am running on zero right now and have both lines blocked off

 

Yes, a failed O2 sensor can potentially cause major fuel economy issues. I posted a long while ago about the incident I mentioned in my first post here. Buddy of mine who ran over a trash bag and it melted to the body of the O2 sensor. He was losing nearly 5 mpg within a week of that happening.