Power Loss - I'm stumped! 99 GTP

[Mr. Cynical]

Good day, AF'ers!

Let me tell you what's just happened:

Last Friday, I stopped in and got my car serviced. Everything checked out well, and in fact, it felt really strong. Friday afternoon, I took off on about a 250 mile drive to a friend's house, and everything is all golden.

Saturday afternoon: We're stopping to get some food at a restaurant. I notice that there's a sound I'm not used to coming from underhood. I popped the hood, and deemed it to be that maybe a pulley was making noise. I'm not the most terribly mechanically retarded, but that was the best I could do on short notice while dressed up. I made the call to run it back to her place, since it *was* a nasty rainy day, hoping that maybe it was weather related.

Sunday afternoon: Noise is gone. I had to buy gasoline, and it was hard to find premium. (small, small town). I eventually found a place selling 91, and filled up. Dumped in a bottle of octane booster, just in case, and took off. Everything felt normal. No noises, plenty of power.

About 100 miles in, I noted a lack of gusto. I couldn't hear anything strange, but it was definitely weak. Mind you, I couldn't really stop; I had a dog in the back that was three days removed from ACL reconstruction surgery. Had to get her the heck home. In goosing it (the car) a few times, I noticed that it wasn't really downshifting when I'd go WOT. I also noticed that the boost guage wasn't going all the way up. Maybe a third to halfway. Pulled into the garage, and parked overnight, deciding to check it out today once the dog's better settled.

Monday Afternoon: I take off to check things out. I notice really low power. Boost guage doesn't climb at all. Parked back in garage after about 4 miles, and came here to post this.

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So, could this be as simple as a loose belt? It's a gatorback, and has about 40k miles on it. The tranny is recently rebuilt (after the second broken flex plate). I've got 85k on the beast. I'm due to change the S/C oil in about 5000 miles.

Any ideas as to what I should be looking for? Anything is appreciated!

Your Pal,

Mr. C

[Mr. Cynical]

Update:

I'm no longer stumped. The belt that seemed fine on initial inspection was, in fact, loose. I just popped the hood, and it was laying there unattached to anything.

On the bright side, there's no damage, as yet, and this is a perfect excuse to not only change the S/C oil, but to consider dropping to a smaller pulley. Bad side: I'm going to have to go to a shop to get it done; I've torn my rotator cuff, and am not too incredibly good with torque for the time being.

Either way, I hope this helps someone in the future.

[BNaylor]

Originally Posted by Mr. Cynical

Update:

I'm no longer stumped. The belt that seemed fine on initial inspection was, in fact, loose. I just popped the hood, and it was laying there unattached to anything.

On the bright side, there's no damage, as yet, and this is a perfect excuse to not only change the S/C oil, but to consider dropping to a smaller pulley. Bad side: I'm going to have to go to a shop to get it done; I've torn my rotator cuff, and am not too incredibly good with torque for the time being.

Either way, I hope this helps someone in the future.

Are you running the stock 3.8" SC pulley? That is unusual for a Gatorback to jump the pulley. Are you sure you don't have a tensioner problem or a idler pulley problem?

[richtazz]

I agree with Bob, sounds like an idler or tensioner pulley issue to me. Goodyear belts are one of the best out there, especially in performance applications.

[Mr. Cynical]

Good afternoon!

I've had a week where I've been busy, but I haven't had to drive at all.

So, I'm all sorts of ready to try to do this myself!

I just went out and threaded the belt into place. It's so loose, it's like it's not even worth having it on there. I can't imagine that the belt would be stretched, so I have to assume that it's either the idler or tensioner that you guys were talking about here.

In looking at the one I *think* is the Idler, I noted that it had something that looked like an arrow pointint at a box. Looking at it, the arrow was at the far left side of the box, possibly even outside of it.

Before I go running off to a mechanic, is there any way I can adjust this myself?

[Mr. Cynical]

Update #2:

Problem solved. What I thought might have just been some protruding piecec of hardware...well, it turned out to be the remains of the smooth idler pulley at the bottom. Apparently, it just flat-out detonated on me. New pulley installed, new belt in place as well (the other one, while in decent shape, got a slash in it when it came loose).

Now, for some new gaskets, and to figure out the sputter after WOT, and good as new!

[richtazz]

The sputter at WOT could have been caused by the belt issue. Drive it for a while to see if it comes back.

[BNaylor]

Originally Posted by Mr. Cynical

to figure out the sputter after WOT, and good as new!

When was the last time you installed new spark plugs and/or ignition wires?

If the high rpm/WOT sputter or misfire continues then that would be a good starting point. High RPM misfire is typically a bad spark plug(s) or an ignition related problem. Good luck!

[jessep28]

(here comes a stupid answer)

If those don't work, try this for a diagsontic tool:

http://www.creativedice.com/productinfo.html

[richtazz]

Hey JEsse, that is great. I know a couple of "mechanics" that must use those. Do they make an auto parts version? If so, I bet it's standard issue at the Zone.

[BNaylor]

Whenever I get stumped I use one of these. It is the same crystall ball Mr. Goodwrench uses at the local Pontiac-Buick dealer.

[Mr. Cynical]

Originally Posted by bnaylor

When was the last time you installed new spark plugs and/or ignition wires?

If I have to admit...never.

It's something I have been looking at doing for a while now, honestly, since it started doing the sputter. Here's what it sounds like:

I'll hit it, WOT from a rolling start, and when I take my foot off the gas at high RPM, it sputters once or twice on the way back down immediately after I release the pedal. pop pop! Not quite a backfire, type thing, but it definitely sounds like something that needs fixed.

Seems like everything just came on all at once!

[BNaylor]

Originally Posted by Mr. Cynical

If I have to admit...never.

It's something I have been looking at doing for a while now, honestly, since it started doing the sputter. Here's what it sounds like:

I'll hit it, WOT from a rolling start, and when I take my foot off the gas at high RPM, it sputters once or twice on the way back down immediately after I release the pedal. pop pop! Not quite a backfire, type thing, but it definitely sounds like something that needs fixed.

Seems like everything just came on all at once!

Sounds like you are at point where these issues will pop up. When it rains it pours. With 85K miles I'd recommend just a basic tune up. Spark plugs, wires, fuel filter, air filter and PCV valve. Also, it is a good idea to clean the throttle body with carb or throttle body spray cleaner and clean the MAF sensor with electrical contact or MAF spray cleaner.

On the spark plugs and ignition wires stay with the OEM AC Delco. Good luck!