18 mo ABOUT chasing this one.

at 1,500 rpm to 1,750 rpm and shudder like a cylinder is out. 1,800 and UP perfect. Hard on the throttle and the shudder is back.
I have replaced:
Injection
Plugs
Wires
Coil
Air flow
Checked
All bolts
Joints
Mounts
Now what?
This is the 1984
Still have the 1982 no REAL buyers. Had a $2,500.00 offer on the car but he could not get the money from his wife.

What do you mean by "injection'?
Were the fuel injectors replaced or tuned?

This sounds like an intake air leak to me.

There are a lot of places that the leaks can happen, from the intake throttle body gaskets to the vacuum lines. Check them all and ensure your timing is correct. There are also two vacuum lines going to your timing distributor that can have an effect on running conditions.

More info
All injection parts are NEW BOSCH or PORSCHE parts not take offs from parts cars.
Can I use the Either trick to SNIFF out an intake leak on theses cars or will they go BOOM!
Those who do not understand you get starting fluid (Either) and start the car let it idle then spray a VERY LITTLE around the gaskets and such if the engine RACES then that is your leak.
Thanks guys will play with this one Saturday 12/3/2011 and ALSO talk to another GEE I WANT A PORSCHE BUT person on the Blue car.

lrpman;7426 wrote: More info
All injection parts are NEW BOSCH or PORSCHE parts not take offs from parts cars.
Can I use the Either trick to SNIFF out an intake leak on theses cars or will they go BOOM!
Those who do not understand you get starting fluid (Either) and start the car let it idle then spray a VERY LITTLE around the gaskets and such if the engine RACES then that is your leak.
Thanks guys will play with this one Saturday 12/3/2011 and ALSO talk to another GEE I WANT A PORSCHE BUT person on the Blue car.

Some may disagree but I don't find chasing vac leaks with starting fluid to be a problem. Chasing vac leaks is different than using starting fluid to start a car in order to diagnose a fuel problem. I haven't ever seen any adverse effects either short or long term from using starting fluid to find vac leaks.

KilnRed;7438 wrote: Some may disagree but I don't find chasing vac leaks with starting fluid to be a problem. Chasing vac leaks is different than using starting fluid to start a car in order to diagnose a fuel problem. I haven't ever seen any adverse effects either short or long term from using starting fluid to find vac leaks.

It did not BLOW UP or even get excited when I sprayed the JOINTS. I checked ALL the lines, wires, cap etc.
BUT I might have found the problem MAYBE, COULD BE, NOT SURE that should cover it.
I found the coil I had put on the car was a spare race coil from an old V8 I had, ACELL brand. (old was shorted for sure)
I am wondering if the fact the the shakes goes away at HIGH RPM and the range is 1200 to 1500 could it be the coil???