2002 Grand Am GT losing power

[ex-x-fire]

Test the comp. tester on a another car.
Is the engine in that Grand Am quiet? I had one that had a noisy valve train, didn't have any power at all, no codes. The knock sensor was retarding he timing alot( according to the scanner), unplugged the knock sensor & it ran great.

[Axe_1]

Thanks guys, I replaced both Schrader Valves in the Comp Tester and it works now. They just sat too long without using.

I got about 150 PSI across the board. They were all between 148-155 so that's close enough for me.

I just ordered some new Plug Wires and I hope to check the exhaust down pipe and knock sensor tomorrow. After that I'm kind of stumped again.

Axe

[Tbay99Venture]

Well it'll be nice if it's the spark plug wires. Were you able to check the fuel pressure while loading the engine? (Power brake it, maybe?) Is it possible there's a fuel restriction that doesn't show up until you need some volume. Dropping the tank is not friendly to a bad back though. Wouldn't want to suggest it needlessly.

[Axe_1]

No we've had T-Storms almost every day and I'm working in the driveway.

I would really like to get this thing running soon. I already missed my yearly trip to Nashville & Little Rock to see friends, and would at least like to have it for show in Memphis on Aug 1st.

We'll see..

Thanks again for the suggestions guys. I still have plenty to do if I can get a dry day that the heat index isn't 115 degrees.

Axe

[Axe_1]

Diagnosed for now. A thousand people said it but I kept putting off dropping the down pipe. A guy named racer91 over at The Auto Lounge suggested that I just pull the O2 Sensor before the Cat Conv and BINGO!

Now I'll probably spend most of the day surfing for a decent High Flow Cat system I can afford. My wife would be happy if I went headers and all, but I don't really have that much to spend today.

Thanks again everyone.

Axe

[60dgrzbelow0]

Axe_1 ... Because you drive your car at such high speeds... I'd be curious to know whether you've been using a Racing Oil high in ZDDP... such as Valvoline Racing Oil. The Zinc and other exotic metal protectors and metal hardeners in such oil can often coat the O2 Sensors and Platinum Screens inside Catalytic Converters and wreak havoc on ECM/PCMs. If so... I'd like to know when you switched over to this oil... and about how long it took for this problem to raise its ugly head.

[TurboGTU]

I was reading along and was thinking Cat converter or crank sensor cable to ICM (they love to melt on the rear exhaust).

Had people come to the shop with aftermarket cats and they all set off the SES light cuz the don't clean the exhaust like the stockers do. If your state requires emissions test then fine. But I'd rather just disconnect the cat from the back pipe and gut the cat with a slage hammer.

[Axe_1]

60DB0 this is an all stock DD. I normally don't go above 75-85 MPH, but was out one night alone on a long deserted Indiana road and stepped in it a little to see how it ran. I would have taken it higher but the road was a little wavy and that's as far as I trusted.

You have to remember that I've been riding on and driving fire trucks since '89, and been a promoted driver for the past 13+ years. After dodging downtown traffic at 55 MPH in a 60,000-80,000 Lb vehicle, 120 or so in a car on a deserted road just feels like cruising.

The last oil change I was at work (24 hr shifts) and my wife took it to Walmart. At least she did get their synthetic, whatever they offer. After that we did start having charging problems and I was afraid those morons broke a sensor, either accidentally or otherwise.

No offense to anyone working at Walmart. I just normally don't trust my cars to anyone, but have been having some health issues and gave in.

I think our biggest problem was taking our daughter back and forth to college. That commute alone was over 80 miles a day, with about half being in heavy traffic. (20+ miles each way x4 trips).

Axe

[Axe_1]

TurboGTU, I considered attempting to clean or gut the original also. I have access to cutters/welder, etc.

Currently no emissions testing in Ohio because they damaged too many cars when they had it. I do live in one of the 3-4 OH counties that had it, another reason I prefer classic muscle.

Axe

[Tbay99Venture]

The last oil change I was at work (24 hr shifts) and my wife took it to Walmart. At least she did get their synthetic, whatever they offer. After that we did start having charging problems and I was afraid those morons broke a sensor, either accidentally or otherwise.

Reminds me of long ago when I was just on my own & didn't really have a good place to do oil changes & dispose of the old, etc. So the fast-oil-change places will top off the fluids for you. Which meant I never noticed "where is all the fluid for the clutch going?" until one cold morning when the master cylinder seal give a squishy pop sound and the pedal went to the floor.

[02GT_Skyhigh]

Change the Cat and watch your power come back! After I did my head gaskets, I had the same damn problem about 15-17k later... Put a magnaflow cat on and I fell back in love. hahaa

[bob442]

I'd go with the cat on this one aswell, just unbolt the down pipe to verify. I had the same issue with my MC at 90,000 km

[Axe_1]

Hi guys, been away for a while but cleaning out the cat guts did it for now. I'm having some problems with my house so the cars are all on hold again. The GA is running decent, but I have had to replace the fuel pump also since my last post.

Thanks again,

Axe