I have 2001 xl 4.6L 4x4 with 104k on it. Great truck love it to death. about a week ago I had to fille up was very on the tank, left my truck idling. After putting 10 gallons in the tank the service engine light came on. after reading in the maual about the causes I thought that maybe the station had sold me crappy gas. I added octane boost and refilled a few days later adding more octane boost. the light remained on. I talked one of the dealers into resetting the light for me. I ran the truck for a few day with no problems, but noticed that as I got to the bottom of the tank again the light popped back on. Any ideas on what that can be?

 

Go get the codes read so you aren't clueless.

There are dozens of possible causes and hundreds of possible fault codes.

Guessing won't help.

Steve

 

went by autozone, got a EGR message but didn't specify which component. The guy said it was prob either the EGR valve or the sensor. The dealer was able to clear the light for me and it ran for a few days without returning. Which one is more liekly to have failed? and is it a pain to replace? I am not mechanically inclined. Thanks

 

Again, without the EXACT fault code, it is imposible to help.

Go back and GET THE CODE(s)!

Fault codes do not specify components. There are only a data point to be used in a diagnosis.

Steve

 

alright man i had the exact same problem a while back, i hooked up a code reader and it said EGR failed i took it to a nearby mechanic and they said my sensor had no voltage meaning it had failed...they hooked up a new one it was about 80 bucks...after that problem solved and the code was clear
hope that helps...good luck to ya

 

Just by the by, I think filling your truck while the engine's idling is wasteful and dangerous....and possibly harmful to the fuel system since it depends on a certain amount of pressure in the tank owing to the anti-evaporation measures in there, depressurising the tank by opening the filler while it's running might cause all sorts of problems, perhaps damage to the pump if there's a fair amount of pressure in there, like when the weather's warm...

 

Yeah I got a p0402. EGR excess outflow. I picked up one of the sensors but I can't seem to find the part in the truck. Where would that be located?

I know I need to shut the truck off, had a little one in the truck and wanted to leave the air running.

 

Drivers side of engine, next to t-body, above the fuel rail, it will ahve 2 hoses from the egr tube running to it.... Both the hoses are different sized also.....

 

Thanks.