I need help!!AAAGHGH

Hi guys/gals, I need some advice..
On my 99 Venture I started to notice that my fuel guage started to act up last week, it will climb to full or empty. as soon as it does this the van starts acting up, downshifting/upshifting ect. the engine light will come on as well.,. With all the info on the forum you guys gave me I decided to look into the sending unit.. Last night after the tank was off I looked at the sending unit and it looked brand new, it tested fine reading 39 ohms empty and around 200 full..same as the new ones out of the box.I decided to put it back togeather saving the money and the van worked fine...for a day. Back to square one, I have cleaned all connections on almost sensors and now am stuck.. I can't seem to believe the new sending unit will fix my problems..someone else said a ground may be the problem and the fuel guage is the first thing that gets affected. I know lots of stories about the sending unit failing but it doesn't affect the rest of the vehicle. I
did have the codes read last week and there were a pile stored. does this sound like just one component? or other electrical problems....
where to next. perhaps I should just put the new sending unit on take the 200$ chance and see what happens,. I can't see it fixing anything though as the guage reads proper until it fails and then immediatly following that the van starts working bad.
Sorry for the long post but any advice would help
Andy

You may have a problem with a wiring harness. Right off hand I beleive there are 5 or maybe 6 connectors between the sending unit and the computer. Any one along there could be flaky. I would particulrly look at the connector behind the driver's seat under the vehicle. I've heard of more then one person who has had issues with that one.

I myself had an intermitten problem where the car would either stutter, act like it would die, actually die, or not start. It all traced back to that connector and the contacts needing to be bent back out.

The sending unit enters into the engine managment in no way. Any connection is only incidental and not causal.

FYI, there are some automotive connectors with "hardened" contacts (i.e. they use an alloy that is stiffer so that it doesn't wiggle loose, but that doesn't bend back very well) that, once they wear down enough to make bad contact (i.e. through corrosion and vibration) they need to be replaced. I don't know the specifics on your connectors, but it's something to keep in mind if you suspect bad connectors. The good news is that they tend to provide a more reliable connection for whatever lifespan was designed to. The bad news is that, when they begin to go, they really need to be replaced. They can be bent, crimped, etc. for a while, but they won't be as reliable.