tlsmith1999

This sounds like a perfect reason to own more than one 928. I could swap the brains and see if the problem is fixed.

SeanR

Tim, there are a few other owners out there in your area. I hope someone will chime in to let you borrow a brain (LH). If I had a spare I'd send it to you, but alas, I don't right now.

I want to see some pictures of her........

tlsmith1999

Well, I haven't made any progress on the power issue, but I did get it cleaned up inside and out last night/this morning. I will get some pics up soon.

Found another problem with it this morning; the passenger side head light is way dimmer than the driver side. I replaced the bulb, but that did not help. I am guessing that side is getting a poor ground, or a corroded correction. Haven't had any time to trouble shoot it yet, probably tomorrow.

John Speake

How many miles on the car ?

tlsmith1999

89K. But the last year or so the PO has not driven it much.

John Speake

The MAF should be OK at that mileage. Try to get a diagnostic tester on the car, that could help make a diagnosis, and also identify other possibile issues.

WallyP

As has been mentioned, a partially plugged exhaust can cause this problem. You should be able to determine if this is the problem.

A partially plugged exhaust is primarily affected by the quantity of exhaust gases produced. If you increase the engine RPM level by applying minimum throttle, the RPM level should go higher than if you increase RPM level by applying full throttle.

On the road, the top speed should be higher if you apply minimum throttle to increase the speed than if you go WOT.

If the problem is in the control systems, the RPM level where the problem occurs will either be consistent, or will vary with engine temp or some other control variable.

tlsmith1999

I am still working the power issue, but fixed the dim headlight (broken ground wire). Also found that the horn was unplugged.

I am going to take the car into town Monday and have the diagnostic port read. Will keep you all updated.

tlsmith1999

So Mat at TWPC here in Austin figured out why it was running so weak. Turns out Sean (among others) was on the right track, it was a fuel problem. Mat found that the throttle cables were off of a roller. This was causing a lot of play in the cable, thus when I floored it, the throttle was not opening all the way.
I am glad it turned out to be a cheap repair.

Thanks to everyone for the help and suggestions.

M. Requin

Excellent outcome, congrats, and thanks for posting the followup!