'92 GTP was low on power, now won't start

[crazyd]

My '92 GTP refused to start after I pulled into a parking lot last night. I'd driven it there with no problems other than it being low on power and getting the "chuggles" if I tried to get more out of it, but only between 2000-4000rpm. Once past that point, though it didn't feel like it was all there, it did pull smoothly. I first noticed it on Sunday, and had decided it was probably just a clogged fuel filter (which I haven't changed for about 30k miles). Planned to do it today, but I tested the fuel pressure and it was at 41psi and holding, so I didn't think it was urgent.

The only other symptom is it sounds really odd when I'm cranking it, a little slower than usual and without the normal tun-tun-tun sound, which deteriorates into this continuous swishing sound the longer I crank it. I can't accurately describe it so I've uploaded a youtube vid here.

This also started several days ago before it completely refused to start, so I don't think anything catastrophic has failed.

Here's what else I've checked:

• Suspected TPS, so I pulled codes. 6 #12's and nothing else, so the ECM seems to think everything's hunky-dory.
• Inspected vacuum lines. Did this while the engine was running and no disconnections or hissing noises noted.
• Pulled timing belt inspection cover, belt is tight and like new (replaced about 20k miles ago), appears clean inside, no "hairs"
• Inspected plug wires and ensured they are all seated properly
• Oil is clean, 10W-30 synthetic, no coolant contamination
• Exhaust is clean, no smoke or funny odor; cat replaced about 10k miles ago
• Replaced ignition coils & ICM

I don't think that the timing chain broke, I think I replaced it at the last rebuild about 20k miles ago and it wouldn't break just from shutting the car off.

I have a fuel pump activation switch on the dash, and I know the fuel pump is running and pressurizing to 41psi at the injector rail.

Anybody got any other ideas?

[Schurkey]

Inspected plug wires and ensured they are all seated properly

Plugs fouled? Did you pull them and check? While they're out, perform a compression test.

Replaced ignition coils & ICM

Do you actually have spark?

What is battery voltage during cranking? What is battery voltage with NO load?

You have fuel pressure, do the injectors fire?

[pocket-rocket]

It almost sounds like not all cylinders are building compression.

Is the timing belt turning while cranking? When the 91 ate the belt it was still nice and tight and looked normal until the belt got removed. Taking it off revealed the teeth had been sheered off of it at the intermediate shaft so the belt couldn't turn while cranking.

[crazyd]

Yeah, the timing belt isn't moving. Little soon for a timing belt to go after only 20k, but no big deal to replace it again. Got a new CPS, ICM and coils in the process.

[crazyd]

Found the problem..

Timing belt's missing a few teeth....

[1988GTU]

That'll do it!

[pocket-rocket]

Sort of like the 91, except it shredded through the belt backing lengthwise some as well. At least you found it and it's a relatively simple fix

[crazyd]

Yeah, I finished it up and got it running again last night. There didn't seem to be anything wrong with the actuator, but I replaced it anyway. It's no wonder this motor got such a bad reputation, if I'd had to pay for another timing belt repair (this is my second failure in 2 years) i'd really be pissed...