1988 300zx n/a won't rev past 3k

I picked up an 88 300zx 5 speed that needs some work and I'm having a hell of a time figuring it out. The engine will fire right up and idle rough. If you rev it up, it will crawl to about 3000 RPM with the pedal to the floor. It will hold at 3k for a second or two before bogging down and slowly dropping to below 2k. At around 1900, it will recover and try to rev up again, only to stop at 3k and repeat. My friends said that they smell fuel coming from the exhaust when it bogs down, but I haven't gone back there and smelled it myself.

I started by pulling trouble codes for the TPS, MAF, VSS, and fuel pump. The speedo and fuel gauges don't work, so I skipped those codes. I changed the MAF sensor and tested the wiring, and changed TPS but didn't check the wiring. I borrowed a timing light but it was too bright outside to use it. I pulled the #1 plug and did a compression check (130 psi).

Any ideas? I did pull the distributor cap off to take a look and it appears to be out of time, but like I said, it was too bright out to check with the light. Does this sound like an engine that is out of time?

I forgot to add that there is backfiring through the intake.

Yes, it does sound like there is an issue with timing potentially. You'll probably get more information specific to your car if you post in the 300zx forum. This could be a common issue that has a known fix.

http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=1141

-Rod

That's my guess too; the valve timing is off. Perhaps the cam chain or belt has become too loose or the tensioner is bad and it's skipped a couple of teeth.

I would suggest do not run the engine again until you fix this.

This situation leads to a lot of burning fuel going down the exhaust which can burn exhaust valves and damage the catalytic converter.
Also, the cam chain might slip even further, which may result in valves hitting pistons - a very expensive problem.

Well, the oil pump is leaking into the timing belt area, so it very well could have skipped some teeth. I did notice that the compression on #1 was bleeding off a bit, but I didn't give it much thought since the engine has almost 200k on it. I'll try to get that apart over the next couple days (my garage is taken so I'm stuck in the driveway...). Thanks.

The car is finally in the garage. I pulled the timing cover off, but each gear was only off by one tooth, which doesn't seem like enough to make it run so terribly. The oil pump is behind the crank gear, so I'll change it while everything's apart.