No juice past 5k rpm, flashing CEL [Archive] - GrandAmGT.com Forum

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Upshift
10-09-2010, 03:41 PM
Hi everyone, for the past few months i've noticed a degredation of the performance of my 2003 olds alero V6. 0-60 times last I measured were a paltry 10 seconds. And I was topping out at 100 miles an hour. Then a few weeks ago I was topping at 80 and started losing a loss of performance past 5500rpm on 2nd gear. Finally this week I have been topping out at 120 floored ith some massive slowing at 5000 rpm on 2nd. Today at 5000 RPM on 2nd I had no more and the check engine light started blinking, I promptly slowed down and stopped untill it stopped flashing. Note that the CEL was on steady before as I have a dead Catalytic converter(doesn't matter much where I am as we dont have periodic emissions checkups). Also for at least 4-6 months my low end has been a bit lazy.

I'm worried as to what the issue might me. I know for a fact that the transmission locks up firmly and properly onto each gears so i'm thinking it rules out that possibility. I'm wondering if it could be a case of bad injectors or something. Also note I do my oil changes every 5000km(3000 miles). use good quality fuel and already checked the air filter.

Please help!

FuriousG
10-09-2010, 03:52 PM
A "dead catalytic converter" sounds like an obvious answer to me. When my cat went out I lost A LOT of power on the top end. It got so bad that I had trouble reaching 70 mph. If your catalytic converter is clogged then your exhaust has nowhere to go and ends up backed into your engine. For me, that caused the exhaust manifold to blow the heads off two of the bolts that held it on and the heads had to be removed to drill them out. Get your catalytic converter fixed ASAP and then see if you are still having problems.

AaronGTR
10-09-2010, 04:29 PM
^Agreed. Get your catalytic converter replaced and that will probably resolve the issue. Right now it's probably like you are trying to drive around with a sock stuffed in your exhaust, and obviously it's not going to work very well. The flashing CEL typically means very bad misfires, which could be caused by the exhaust being backed up.

Upshift
10-09-2010, 04:46 PM
Alright will do. Anyone know how much the parts and labour can come up to? I hope replacing the cat also helps the car regain some of the fun I used to have with it :P. It's bad when you cant even beat a toyota echo anymore lol.

AaronGTR
10-11-2010, 09:35 AM
It depends. A factory replacement cat comes with the entire downpipe and flanges and gaskets. Everything that is needed to directly swap it out. Dealers charge quite a bit of money for them though, and even on gmpartsdirect.com it is over $300 iirc. You can get an aftermarket replacement cat much cheaper, but it will need to be welded in and may also need a flange and O2 sensor bung added behind the cat. Most exhaust shops will do this though and it's still much cheaper. Only thing is, depending on what size and type of replacement cat you get, it may not be as efficient or warm up as fast as the stock one and may set off a check engine light. To remedy this you would need a rear O2 simulator (to trick the PCM) or get a tuned PCM with the rear O2 sensor codes deactivated.

G.I.Ceo
10-11-2010, 10:17 AM
If you are spending $300 for a new catalytic converter you can get a after market one all ready to go and all you have to do is bolt it up. Milzy Motorsports builds a high flow direct fit down pipe with catalytic converter. I have used it for a few years now and it less restrictive then the stock one so it has more flow. I noticed a difference when I bolted it up even on a stock system at the time. I had the same issue with my catalytic converter going out so I just swapped it out with a MMS one. http://milzymotorsports.com/

Upshift
10-11-2010, 08:03 PM
Tempting but problem is, shipping that to where I live will cost quite a fortune. Plus I need to change it this week so i'll pay up for OEM for now.

G.I.Ceo
10-11-2010, 08:10 PM
Tempting but problem is, shipping that to where I live will cost quite a fortune. Plus I need to change it this week so i'll pay up for OEM for now.
Oh your in Canada. Yeah that would cost you a small fortune to get that shipped to you.

Upshift
10-14-2010, 12:11 PM
Well the car is currently in the hands of the local(and trustworthy) mechanic. Ill keep you all posted on the final diagnosis and results of the fix.