I don't know shit about domestics so was wondering if anyone had some ideas. My girls parents have a 99 Catera with some issues. When they went to drive it today it started making a knocking sound and the check engine light came on. It also lost quite a bit of power and stalled out. The car did restart and they had me take it to run a diagnostic. The codes show
P0300 Random Cylinder misfire detected
P0301 CYL #1 Misfire Detected
P0302 CYL #2 Misfire Detected
P0304 CYL #4 Misfire Detected
P0305 CYL #5 Misfire Detected
P0306 CYL #6 Misfire Detected.........they said the knock was coming from the top side. This was just an out of no where occurence. The car has ran awesome to this point. Has a little over 90,000 Miles. All the fluids were good. I was wondering if maybe the timing belt slipped and the timing is way off and a piston is banging a valve or something. (Just an uneducated guess) The guy at the shop (not a mechanic told me that it wasn't possible because the compression was good all the way across) Dumb answer I think, but who am I. SO the point to this thread is does anyone have any ideas as to what the problem could be and is anyone interested in fixing it? Let me know.
Thanks

 

how does the misfire replicate? have the service intervals been kept?

 

As far as I know it has been serviced when needed, they just got the car 6 months or so ago. What do you mean how does it replicate?

 

I have heard certain GM's have problems with random misfiring. Also, I don't think that that is an interference motor so you shouldn't have heard any piston against valve noise...Maybe it is a case of really bad gas? Was the car under a heavy load when it happened? More details might help a little bit.

 

Gas may have something to do with it, they put the cheap shit in on accident. It wasn't under a heavy load just regular driving. What would te banging be though. It sounds like what rod knock does, but it's coming from the top end

 

it is an interference engine

 

With all the codes it is shooting out, it would be something that is related to all.

Cheap gas and/or a failing ignition control module (not sure of Caddy's set up- ie single coil packs for each cyl) might be causing the misfires. You might be hearing what is called "spark knock".

 

check the fuel pressure. pump may be going out.

 

Just tell them to buy my Caddy. It's weird that all the cylinders are misfiring. Could low octane gas really do that?

 

Check fuel and spark.