Need advice...

The LT-1 in my stock 83,000 mile Firebird Formula (with automatic) started running really rough today, as if it were running on only six or seven cylinders. It also was pinging when accelerating while doing this. It now runs rough all the time and idles lumpy as well --- again, as if someone pulled a couple of spark plug wires off. All of the factory gauges are reading normally, btw --- temp is normal, etc.

This all happened after I had opened it up a couple of times today.

I remember that back before I bought the car, there was another stock LT-1 'Bird that a chick was trying to sell that ran the exactly same way. I thought the engine was damaged, but she ended up selling it cheap to a dealer who fixed it overnight, so I'm hoping mine may have a similar easy fix...???

I'd appreciate any ideas on what might be wrong with it. Thanks for any help you can give, and hope this isn't the ninetieth time you guys have had to answer this question...

 

Thanks for the help.

 

Missed this probably because it was at midnight and it was back down the page before I logged back on. Any check engine light? Does the sound come from the top or bottom of the engine or elsewhere? The more specific you can be on the noise and where will help a lot. Is your oil pressure where it normally is? If it happened after wot runs, it could be something internal.

 

Ditto on SES light... if it is, have it scanned.

How's your fuel pressure? Could be a dying fuel pump.