I have a mostly stock, excluding exhaust and intake, 97 Formula. Currently with 95000 miles on it. I generally take extremely good care of this car. I've noticed a significant performance decrease in the last 5-10 thousand miles.
I used to love the power and torque of this car, I could chirp the tires in third gear and even in forth a tiny bit when I tried, not bad for stock. Now it seems like I can almost stall it by letting the clutch out too fast in first, and can barely chirp the tires in second. I was wondering if anyone had any simple suggestions. Could it really be that the LT1 is tired already? I haven't had a blow-by test done yet, would it be a good idea?
My only thought is that last year my water pump went, and maybe there's a chance it overheated, but I don't think so, and I do know that the new pump I had put on is not as good as the GM original, and the car runs warmer. Not sure if any of that is significant, if any overheating damage or warm running temp could cause a lack in power.
I've also been curious for a while if anyone else has the same A/C problem that I do. My A/C pump draws gobs of horsepower, even when the engine was running great, but now, if I turn my A/C on, I can't even bother ever running the car in 6th gear, or it'd never accelerate.
Anyway, all thoughts are appreciated!

 

how many miles on the car? how old is your opti/cap/rotor? what about plugs/wires? o2 sensors?

 

any CEL?

 

Plugs and wires ever been done? How about the coil?

 

95,000 miles on the car and engine as it's all original.
The plugs were just done last summer, not more than 10,000 miles ago.
I doubt the wires have been replaced yet.
No check engine light.
I've only noticed the loss of power gradually over the last 10,000 miles or so.
It still runs fine, totally smooth, just a little weak is all.
Any thoughts?

 

It is extremely unlikely the engine is worn out. With the low tension rings, good machining and good injection, these things exhibit VERY little bore/ring wear even at twice the milage you have.

I am with the others in suspecting more tuneup type issues.

 

Def check the wires at night, see if there is any arcing should be a nice blue light show for you if there is.

 

ya try some tune up things...check your injectors and do a fuel system clean...catalytic convertor could be slightly clogged or backed up to if you even still have one and heave never changed it out

 

Any advice on cheap/good cat converters?

Also, anyone else have the same A/C problem I do, that it seems to suck up about a third of your power? Thanks.

 

i noticed that too at 112k the clutch was the problem it was slipping.. also the a/c on my drags really bad. i can feel it kick on and off and shifting the gears it brings the rpms down fast and i get some sort of buck when i shift

 

Still at a loss on this, wondered if anyone out there might have some thoughts. It's definitely low on power, if I had to guess, probably 40 HP or so less than it should have, reminds me of my old V6! But like I'd said, it still runs real smooth, just under powered. I've done all the basic tune-up items, had the computer monitor run to check all sensors, filters changed, fuel injection cleaned, new plugs, etc. I had a compresion test done on two of the easier cylinders to get to, and was told it was great, 150psi. Is that great? Should I invest in a compression test on all cylinders?
One shop sugested that because there was a water pump leak at one time, that water could have gotten into the opti-spark. Is there any chance of that, and could it cause me to lose power, but still run right?
Anyway, I'm totally lost, the cars in great shape and always ran great until recently, just affraid it's still getting worse.
Thanks!

 

I'm not 100% but I think that PSI is a tad low for an LT1. I believe even for the mileage you should be still making 180~.

Good chance some moisture got into the opti, but since yours is vented, that would've helped it from causing any big problems. If you store it, it could've gotten some corrosion in the cap and that'll weaken the spark. Wires would be the easiest, and if you haven't done a fuel filter I'd sure as hell do that one!

GL

 

Have you checked the plug wires? Other than what you have done I'd say you should invest in a compression test kit and get all of the cylinders checked out b/c 150 is a bit low. Check all the cylinders and that will help.

 

+1, get em' compression tested. If I remember 170-180 is the norm.

 

Aside from rings, are there other components that could have been hurt by overheating, that could have an impact on horsepower? How much is a ring job on this car likely to cost me at a local shop?

 

EDIT: Thinking of wrong thread. +1 for that psi.

 

Plug wires plug wires plug wires! I'd be willing to bet that's your problem, but double check those compression #s too, 150 is definitely too low