power loss 1-3K rpm, needs tips on how to trouble shoot. Options

[tod914]

Car is a 75 2.0 fuel injected w/55K miles. Here is what happened. I took my rear calipers into a "reputable" shop to have rebuilt. When I reinstalled them on the car, one of them leaked. I was really pissed off and had the car towed into the shop. They were told to fix them. They had the car for 2 days "testing" and repairing the brakes.
When I brought the car in it ran fine. Plenty of power.
It was in need of a muffler due to rust and a small hole on 1 side. But, it was fine to drive. After about 30 miles of their "testing", they blew out the side of the muffler and the car really lacked power. I attributed the power loss to the muffler. I replaced the muffler with a bursch.
A fair amount of the power came back. However, there is a deadspot from 1-3K rpm. My friend did a leak down test; less than 10% on all cyls. He adjusted the valves and repaired the torn mps diapram (which i will need to replace at somepoint). the mps repair made the car idle smoother. He did not adjust the mps.
What has been done to the car; new fuel pump, lines, fuel pres reg, head temp sens, plugs, wires, fuel inj triggers, rebuilt aar from aa, new coldstart, pertronix ign., cap, coil, new throttle switch. All these components where put on before this incident.
Any tips on where to start trouble shooting would be great. Needless to say the shop was not paid. My guess is they either beat the shit out of the car or intentionally messed something up. Im in the process of writing a letter to the shop owner. Meanwhile, I would like to get the car running correctly again.

Thanks

[Rusty]

30 miles to test the brakes? Yeah, they really beat the shit out of your car, because it was a "Porsch". Did you get pictures of what they did to the muffler?

I would suspect anything repaired or rebuilt. There are others that are FAR smarter with MPSs than I am, but exactly how did your friend repair it?

Have you disassembled the distributor to see if it's gunked up? Perhaps pulling it apart, a good clean & lube may help things.

[rhodyguy]

contact bleyseng. he has a bunch in stock (mps's,check classifieds). years ago i recieved a parking ticket from portland or. the day of issue my dat roadster was being serviced in seattle. 2 days to replace a caliper for the 2nd time. they must have liked your car.

kevin

[tod914]

Well the name of the shop is Powertech, here in NJ.
And all they do is work on Porsche's. Being im real fussy about my car, they probally didn't like it.

The guy whom repaired it, just repaired the diaphram with an glue adhesive. He was a porsche mechanic for years and seems to know what he is doing. I dont expect the repair to last forever. I will contact Blesing later today for a unit.

I tell yah these F'n shops charge top dollar and do the work 1/2 fast. Pisses me off to no end.

I guess I will start with the distrubutor and see where that leads. Could the throttle switch or a bad decel valve do any of this?

[Part Pricer]

It is possible that you have a worn throttle switch. Normally if this is going south you may experience a flat spot around 3K.

[tod914]

The thing is, the throttle switch is less than 1 1/2 years old. How do I know if its adjusted properly?

[ChrisReale]

Glue does not repair MPS diaphrams.

[Bleyseng]

You can't repair a diaphram!
Any thing you do will affect the MPS's sensitivity and mix control. If its cracked or torn its toast. better it completely rips out then the mix is nice and rich which is great for drag racing.

Geoff

[tod914]

AH ok. So asside from dirty plugs, its not a totally bad thing then.

[Bleyseng]

Much better than a lean condition which burns the heads up so they drop the valve seats out.

Geoff