what could this be, every time the car was started oil pressure is pegged till u kill it, ran fine, oil sending unit?

 

Yup, that's exactly it. You almost certainly have a bad oil pressure sending unit. This is a very common problem with C5's. I replaced mine too, a few months ago. As they say, there are two types of C5 owners... those who HAVE replaced their OPS's, and those who WILL. While a bad OPS won't hurt your engine, don't wait too long to replace this, since if you really DO lose oil pressure for some other reason... you will never know it.

To help verify that you have a bad OPS, try these steps:

1) With the engine running, Verify the oil pressure gauge is FULLY deflected; and also bring up the oil pressure on the DIC panel. It should read something like 130 PSI.

2) With the car off, turn the key to "On" (but don't start the car). Let the gauges do their thing. If the oil pressure gauge pegs out EVEN with no engine running... then it's almost certain you have a bad sending unit. There can obviously be no oil pressure if the engine is stopped.

If you do a search, you'll find some useful writeups on how to do this yourself. You can order the part from several forum vendors, such as Gene at GM Parts House. I got mine from him for something like $40 if I recall.

edit: Here's a link to a thread detailing the replacement of this annoying bugger:
http://forums.corvetteforum.com/showthread.php?t=958008

I hope this helps!

 

I replaced the oil pressure sensor in mine a couple of months ago. The instructions in the post above mine were how I diagnosed it.

In addition to taking out your intake manifold there is a "cut-out" method that will give you access to this sensor without taking so much apart. The instructions on how to do this are in the middle of this thread: http://forums.corvetteforum.com/show....php?t=1588172

The cliffnotes version is that you remove your windshield wipers and the plastic cowl below the wipers. You then have to cut a hole in the fiberglass below the cowl (I used a Dremel) and you will have access to the sensor. Replace the sensor then duct tape your plastic piece you cut out back in place. Reassemble and you're good to go.

 

I wanted to link to the cut-out method, but couldn't find it... it was actually the way I replaced mine. The benefit is that, if the next OPS fails, you can easily get at it.

If you choose to do this path, be sure to cut the hole big enough that you can get your hand through it! You'll need to unclasp the connector on top of the sensor and that's hard if your hole is too small to get your hand down inside.