Hello,

I have a 2001 F-150 4x4 supercrew w/5.4L, it has 217,000 miles on it. I just ran down to the grocery store, 4 miles and it was fine, on the trip back I noticed the temperature gauge wasn't working, all of the other dash gauges were fine, but the engine was idiling at 1500 rpm in park. In the last two days I drove it 570 miles from Albuquerque to Carlsbad and back with the AC on and all was fine, last weekend I was moving my son into his new place and I went to start the truck and it was DEAD. The relays were clicking, even after removing the keys, all electric was gone. I ran out and replaced the battery and all was fine again. I don't know that any of this is related to my current problem, but who knows? With such high mileage I wondering if I may be fighting a losing battle, or hopefully it's a simple fix. Anyone have any ideas?

Thanks for your help.

Paul

 

The high idle in park would indicate a vacuum leak. First place to check is the PCV line elbows.

 

It is just getting broken in.

Sounds like you had a bad battery, Temperature sensor might be bad, which is cheap and easy to fix. And you have a vacuum leak. Most likely in the PCV system because it is common. If you follow the vacuum lines from the passenger side pcv, located on top the valve/cam cover. You will see they go back behind the intake plenum, in the back there is a 90* elbow, that is where is it most likely to fail. Also inspect any and all other vacuum lines, include the pcv as well. There are some things you might want to consider as far as maintenance with your mileage that are simple and can make a big difference. Cleaning the IAC (Idle Air Control) which if dirty can cause symptoms like hard starting, erratic idling and rpm fluctuations while in gear. Or the longer version, cleaning the throttle body, upper intake and egr ports. Also cleaning the MAF (mass air flow) sensor

 

Thank your for the replies, they are very much appreciated. I have had the truck running for the last 20 minutes out in the driveway with the AC blasting, and it's idling normally at 700-800 rpm, and the temperature gauge is working again. Is there any chance that the alternator is going out and that might be causing some of these issues? Thanks for your input.

Paul

 

Another update. After running another 10 minutes since my last post, the idle has gone up to 1500 rpm, and the temperature gauge is no longer functioning, the check engine and oil pressure lights are both on too. Any theories?

 

Did you check the PCV elbows for soft spots or rips?

 

I checked the PCV valves and all the associated tubing, no rips or soft spots. I replaced the idle control valve and the fuel filter and the idle problem seems to be solved. I'm having multiple issues 1) After warming up the temperature gauge goes to zero and the oil pressure light comes on, the gauge still registers pressure, but the light comes on. 2) Also the check engine light comes on, it gives a code P1289 which is the cylinder head temperature sensor, there's plenty of coolant, and according to a thread I found on here replacing the CHS requires removing the intake manifold - a job I'm not about to try. 3) The AC blows warm air.

I have no idea if these problems are interrelated, or if they were caused by my replacing the battery, but either way it sucks, now I'll have to pay a mechanic to work on it.

 

check the cyl head temp sensor...might be a bad sensor...it will trip the oil and temp lights and make the gauge not work. High idle could be also from the sensor...these trucks are very tempermental when it comes to the sensors...they can do some crazy ****. Could also be a vac leak causing the high idle....if so you should be able to hear a hissing sound. Are you throwing any codes ?? You don't need to remove the intake to do the sensor...trust me I just did mine. Remove the alternator and you can get to the sensor with a 3/4in wrench....there is just enough room. takes about 20-30 min to do. That's if you have a 2v motor. The 3v motor you have to remove the intake cause it's on the pass side of the head in the back

 

Alright I got a new CHT sensor and took the alternator out, but now I can't figure out how to get the old CHT out. I can't get the harness off because the clip is facing back and there's very room to move, and the block is in the way of my wrench. Any suggestions, please????

 

Alright, well I got the old sensor out by breaking off the connector and putting a socket on it. Installed the new sensor and all is well, the temp gauge doesn't cut out once up to temperature, the oil pressure light stays off, the check engine light stays off, and the AC works. The CHT is something that carries a lot of clout, for 20 bucks it's too bad Ford doesn't put a backup in.