Fuel Gauge

[The Capt]

Alright here we go. The wife was driving the MM and called to say the check engine light came on, but the car was running fine. She gets it home and I star it up and the check engine light stays on. I drive it down the street and it starts to chug. Eventualy dies in the middle of the road. Cranks but sounded like it was out of gas. Walked home got the truck and gas can put some gas in her and starts right up and runs fine. I tapped on the tank before putting gas in and it sounded emty. The real problems is the gauge says its full. No leaks. Check engine light still on. I know I need to check for codes, but has anyone had anything similar?

[Blk Mamba]

I learned a long time ago to drive by the trip odometer not the fuel gauge, fill the tank, drive a twisty to see if the tank unit is hung up, in the next hundred miles watch the fuel gauge, could be you can unstick it, or the dealer can change the tank unit, drive as much fuel out of it first, if you are going to change the unit yourself.

[NOMARQUIS]

I seem to remember my first MM did his in 2003 when I got it. I believe the dealer replaced the sending unit under TSB? I know my current MM seems to have a fuel gauge that isn't real accurate.

[Bluerauder]

When was the last fill-up? Who put the gas cap back on? If the fill up was very recent, I would suspect that the culprit was the gas cap and you fixed the problem when your put more gas in. It takes a few cycles and several miles for the Check Engine light to recycle.

If the last fill-up was several days ago and many miles ago and the needle never moved off "Full" then you may have a sending unit issue. This should have been a major warning sign for someone.

[Egon Spengler]

Drive by trip FTMFW!

[ctrlraven]

Yep I drive by trip also, I have a mpg tune which gets me about 340-350 miles to a tank and a street aggressive tune which gets me about 300-310. I know my gauge is off. I also pay attention to how many gallons of fuel I put back in. When the Low fuel comes on and I usually can fill up with 16-17.2 gallons after it comes on.

[omarauder]

Had the same problem last summer, the gauge was showing near full but the trip od showed more like less than 1/4 tank. Was like that for a couple of months until I mentioned to a mechanic friend, who read somewhere than the additives in gasoline can coat the sending unit causing flakey readings. He poured in bottle of STP Fuel Injector Cleaner and that fixed the problem about a week later. Since then I've been using the Seafoam treatment.
Even now I still don't trust the gauge.