I'm running out of ideas here, maybe someone can help. My 2002 F150 with 70,000 miles sits alot. Recently it started running rough, especially noticable in overdrive, but rough even with overdrive turned off. It runs like there's water in the fuel. I changed the fuel filter, ran it with dry gas in the fuel and on the next refueling I tried fuel injection cleaner. I cleaned the throttle body and nothing has made a difference. The code reader doesn't detect any faults....any ideas ???

 

plugs, clean out the coil contacts, run seafoam through the top end, clean the MAF wire.

 

I checked the MAF and found it clean, however when I disconnected it from the harness, the truck runs the same as it does with the MAF connected. How do you check for a faulty MAF sensor? As I said earlier, the scanner doesn't read any faults. Does anyone know how to check for a faulty MAF sensor ??? I'd like to know for sure before I replace it....

 

I dont know much about it but it seems to me that if you unplug it and it runs the same then there has to be a problem that has something to do with it

 

the reading on the MAF sensor while engine running should be 0.2 to 1.5 volts.
(measure it using straight pins or other suitable probes of a voltmeter to the + and - terminals with the voltmeter).
raise the engine RPM and the voltage should increase to about 2 volts. if the voltage does not change you need more investigation,; let us know.


but check your PCM if it's faulty or not. MAF should trigger an error ...
good luck .

 

Did you ever solve your problem? I'm having the same issue. 2002 5.4L F150 Supercrew, only 77,000 miles. Mine sits a lot too. Engine running rough. No check engine light. I've replaced air filter, fuel filter, spark plugs, and boots and springs.

Doug Green
Sugar Land, Texas

 

I had a slight miss at idle until I changed the spark plugs today. Now its running horrible. I used NGK G-power. Ive got the 97 4.6 4x4

how could new plugs make it run so crappy?

 

Hope you changed one plug at a time and didn't cross a wire ?
and it's hard to get the boot back on the plug correctly, I would change
the wires, and check to be sure you didn't cross wire a plug or knock
off a vacuum line somewhere

 

All the wires are in the right places. I'm hoping no dirt got into the cylinders.

 

The problem with my truck ended up being an intermittent coil on the #3 cylinder, I found this out when I eventually did get a check engine light. The code was "misfire #3 cylinder"