I have a 2002 4.6 4x4 F-150 today on the way home it started to run rough. around 40 mph it felt like it was chugging, and at a stop light ( with truck in drive and foot on brake) it would run ruff like it wanted to stall but it wouldn't. what could it be? thanks joe

 

It could be lotsa stuff. Start with a code check.....

 

there are no engine or service vehicle soon lights on.

 

With no codes or warning lights, look for the obvious that will not give codes or warning lights. Plug wire could have come off. Check fuel filter. Leaking EGR valve.

 

pretty sure your '02 has COPs, if not ignore this statement, but mine does the same thing and I've been told it's due to the COP's being old and going out, buy a new set off ebay and see if that helps.

 

another possibility for the no light would be someone took the light out when they wanted to sell it? had that happen to me on my truck.

 

if the COP is bad can you buy just one? should i by aftermarket or stock? the aftermarket COP say they put out more power. does it make a difference?

 

Is it ok to drive my truck to the dealer like this? its about 8 miles away.

 

+1 same thing happened to me on a 98 f150 I bought a few years ago.

I bought a set of COPs off of ebay for $100. They have been on for several months and they work great.

DON'T GO TO THE STEALERSHIP UNLESS YOU ARE READY TO SPEND SOME BIG BUCKS! The SOBs wanted to charge me $700 for several things I did not need. Truck was running rough and all it was was a vacuum leak.

 

One more thing.

The service engine light should come on when you turn on the key. If it does not the light is bad or missing.

If I were you I would drive it until I got a code and any autozone can read it for you. Its probably something simple.

 

I have had the same problem for about two months.... at idle after and only after a warm up drive the rpm's fluctuate up and down 2-300 rpm's?????? It doesn't seem to affect performance under power either.

 

I took out the mass airflow sensor, and blew into it. put it back together and it idolled fine. if the sensor is going bad would it cause a code? when i turn the key on only a service engine soon light comes on. no check engine. i bought this truck new from the dealer in 02. would the light come unplugged from the factory?