AUGHHHHH!!! Fuel guage/Engine light on

[AOneill]

Well I thought I had it licked by just pouring in the fuel cleaner..anyway it seemed to help a bit, extinguished the engine light and the van worked great.. It seems like the problems are still there though..I'm getting the transmission shifting wrong, kickdown leading me to believe the map is failing, or will the fuel guage sending unit cause other sensors to screw up. I had the codes pulled and also got a map code.. the only thing is that when the fuel guage works properly, the van seems to work good as well..Should I pull the tank and sending unit and clean it manually or may I be wasting my time..
Thanks everyone for the input, last post I submitted I learned a ton
Andy

[cdru]

The fuel sending unit isn't used for anything other then the measure how much fuel is left. It doesn't enter into any operating parameters that the PCM will use. It's possible that maybe some wires are frayed and are touching when they shouldn't be, but I bet you are barking up the wrong tree in regards to your fuel sending unit being the problem.

To fix it, you are going to have to replace the sender if it tests bad. You can get just the sender though the dealership, but the aftermarket equivilent of sender/pump is just slightly more expensive and saves you the hassle of dropping the tank twice if you pump starts to go south.

Note that the sender isn't always the problem. Mine had been inoperable for over a year (too lazy to fix it) and after running out of gas a time or two, I finally was bothered enough to fix it. Pulling it out, it tested bad. Popped a new one in and it still didn't work. It ended up that one of the sensor lines had worked it's way loose from the bundle under the drivers side carpet and had broke. So it ended up being two different things not making it work.

The sender is very easy test from under the van. Just pop your head under the drivers side sliding door, pop off the wiringing plug and use a DMM to measure the two wires. Proper ranges is 40-250 Ohms IIRC on 98+ vehicles.