Ok here's a little backstory on my problem. On one day returning from work I noticed a sputter under mid throttle acceleration. I thought this odd, but continued on. Two days later on the way to work the car just completely cut out without any warning as I was coming to a stop light. I managed to fire it back up and continued on for about another 15 minutes until it hesitated again. About 5 minutes later it completely stalled out and would not restart. I tried to start it later and was greeted with a hard start that immediately lead to what I can only describe as a massive misfire or stumbling that lasted only for 2 seconds before falling flat on its face. My first thought was the fuel pump. I had been planning on changing this for a little while knowing that it could be a problem (2002 Monte LS with 234,000) so I just ordered one and pressed forward. After changing the pump I checked the fuel pressure at the Schrader and found I had roughly just over 40 PSI. The hard/no start condition still exists. From my research all I can come up with are the MAF, crank position sensor, and the ICM. Although from what I read the engine should still run if the CPS is faulty. Any other ideas? This thing has me stumped. I also have ZERO codes popping up through the scanner as well. Thanks all!

 

Had the same problem with my 2004 SS. Exact same symptoms and no codes.

Eventually though, a code came-up : Crankshaft Position Sensor. It seems that because the CPS problem is intermittent, the code comes and goes. I was lucky, I had it scanned one morning and it came up.

A new CPS fixed the probem.

 

I assume the one behind the pulley.

 

No dice on the CPS. Both have now been replaced, 24X and 7X sensors. Still hard as all hell to start and refuses to idle. It will climb in RPM when I put my foot to the floor while trying to start it. MAF? Fuel pressure reg (I do have nearly 50 PSI though)? This thing is causing me some real headaches. Anyone got more ideas?

 

When your cps goes out, it's usually because it's cracked. So it will start, and run when it's cold, and as it warms up, the Crack opens up, and becomes full of oil, till eventually it fails all together. h

 

I have also seen an o2 sensor act like that. Should throw a code though. Dont suppose you have access to any spares? I'm lucky enough to live close to a cheap wrecking yard, and over the years I've managed to end up with spares of just about everything. Does sound like a sensor though, maybe even your IAT.

 

Pull you ignition control modal and have it tested, mine has gone out 2 or 3 times now... easy to pull and most parts store will test for free

Undo plg wires, unbolt coils and remove, undo wire harness and it's out if I remember corectly

 

So I took my control module in to have it tested and it tested bad. Mind you I left the coils on and that's how they tested it. I had them run the check again and still bad. So I purchased one from another store (promo code to cut price). Installed and the problem exists. So that both CPS's and an ICM swapped out. I'm getting quite tired of this issue. This old thing has become a money pit. Not having a code really bugs the hell out of me. Any other ideas? I am gonna check for spark at the coils to see if they are worth a damn. SMH. Thanks for the help folks!!!

 

Stupid question... How many miles are on the current spark plugs? If you have BOSCH plugs OR you have over 100K miles on the current plugs, change them. Even if that is not the root cause, it's a good maintenance item (use NGK or AC Delco plugs).

You may also want to check here for some maintenance items that may help:
https://montecarloforum.com/forum/fw...0-miles-46078/

Also, check your air filter, make sure it's not caked with junk (I have seen that once, a really filthy air filter and car barely able to run as a result).

 

Plugs are roughly 5000 miles and are NGK. Air filter is same age. New wires as well.