94 bonneville ssei
car will accelerate to about 70-75 under wot....then pings or sounds like, car is missing cat converter, replaced with a leaking flex pipe, if the boost gauge stays at or below zero car will slowly creeo up to about 95 mph max, at which time pinging noise starts as the boost gauge creeps over zero, if i floor it at 95 the car slows to 70, pinging like mad....
things i have done new plugs wires cleaned coils replaced fuel filter, i had thought pump was going out, tested today and car runs with 41lbs of pressurre...when shut off pressure immediatly falls to 10...with switch on jumps to 50, then falls to 10 not sure if that matters it holds 40 while running
is it possible something wrong with supercharger? i bought the car from the local junkyard so i have no history on it other than 4th gear is out....unless i use cruise like i found out in these forums ty ive never owned a sc car so im out of ideas any help greatly appreciated

Sounds like a misfire under load. Go to Autozone or someplace to have your car checked for Diagnostic Trouble Codes.

Check your coils and wires: https://www.gmforum.com/t278818/

Pull a couple of plugs and report on their condition.

If it is not plugs, wires or coils, it could be a misfiring fuel injector.

Do you have a boost gage? What boost are you seeing at wide open throttle?

boost at wot is about 7 it idle it is minus 10

That is acceptable. Doesn't sound like a */c issue. Based on new plugs, wires and checking the coils, my guess is a fuel injector. Next step is to get those DTC'* pulled.

is dtc trouble codes? i have a code reader the only code i have now is po740 tcc converter clucth
before i replaced plugs and wires and cleaned coils i always had po300 random misfire, car runs well at idle ....as long as you dont floor it, which is the only reason i bought it...thought it would be fun to have a sc so far? not so much....how do i check injectors? i have a spare super charger with all peices

DTC = diagnostic trouble code

What you are describing sounds like a misfire, but that should throw a DTC. We may need to talk to BillBoost to see if that TCC code can give you these symptoms. He'* not on right now. If he doesn't post something on this in the next 24 hours or so, send him a PM (BillBoost37) and ask him to look at this thread.

car doesnt throw any more codes, matter of fact ive been driving around with my computer dangling cause ive changed it and havnt put it back cause still dont kno why im having trouble and my code reader is still plugged in so if it throws a code i can check on the fly...i know seems silly but ive been fighting this car for awhile,
do you think i should put my other fuel rail on? it still is complete with injectors....its hard to tell with the exaust leak but i think it runs rough for a few seconds when i first start it, just getting sick of changing things with out any real results....thanks

Check your coils and wires according to the link I sent you in my first response. After that, let'* wait to hear from BillBoost on what he thinks of that tranny code. Swapping injectors might be a good idea but hold off until we hear from Bill.

ok i checked out coils all reading close to 6.05-6.21 bottom side .5 and .6....i pulled the plugs and cylinders 3 5 and 2 the plugs are completely burnt, i mean electrodes melted....cylinder 5 is just hollow its so melted, cant believe it ran....the plugs are new with maybe 100 miles on them, they are acdelco 41-601 this has happened before it was with the previous engine it burned out cylinder 2, but i was using app 606, then i saw in forum it said dont use platinium plugs, so i switched to the ac plugs, why is it doing this? no wonder it wont run right...

I use iridium plugs. Most on the forum don't recommend that, its just a personal preference for me.

You symptoms were very indicitive of a misfire. It pretty much had to be coils, wires, plugs or injectors. Not that there aren't other causes of misfires, but these are the top candidates. That'* why I had you start with plugs and wires even though the plugs were relatively new.

I am concerned about why the plugs are burning up. I suspect that pinging you hear under acceleration is pre-ignition, which can create elevated temperatures in the combustion chamber, and burn up your plugs. Unfortunately, pre-ignition can also blow chunks out of your pistons.

I'm going to ask one of the gearheads to take a look at this thread to see what he suggests.