Chrysler Repair: Transmission gear selector: 89 turbo, jerking, chrysler lebaron, torque converter

Question
QUESTION: Hey!  I got an '89 chrysler lebaron GTS it's a 2.5 turbo, auto transmission, it's not electronically controlled from what I understand since it only has D,1,2.  It drives great but starts jerking back and forth real bad when it's at full throttle or close to it.  When I apply a little forward pressure on the shifter it stops jerking.  Also you can shift the car to ANY position on the shifter selector without the key in ignition or without pushing the break pedal.  I've been trying to figure out this problem but maybe you got some good advice.  Thank You!!!
-roman-

ANSWER: Hi Roman,
On the power output jerking up and down, I would wonder if you might not have a worn, or perhaps 2 or even all 3, engine mount. The turbo has so much torque that over time it will tear up its mounts. If that happens the gear shifter position at the trans can change even though you haven't moved the shift lever. It seems to be related to that mechanical interconnection so that is where to start.
Let me know if that is not it and we can explore the engine functioning itself, but this seems to be a trans-shift issue.
There is no shift position/key/brake pedal interlock, rather the starter relay will only function when the shifter is in P or N.
That should be a great car for you!
Take it easy on the gas pedal and you should get some good/economical service from this vehicle. This trans is less problematic than the etax, but a turbo can tear it up too. It doesn't have a torque converter lock-up clutch for that reason as well.
Roland
PS I have the '89 with the 2.5L non-turbo w/3 speed auto. in a Lebaron Coupe

---------- FOLLOW-UP ----------

QUESTION: Thanks alot for advice!  Yes the motor mounts were pretty bad but i guess i never linked the problem to that.  So I went ahead and replaced them all.  Outcome.  Much better but I did discover that it does the same thing, even when you're in 1st or 2nd gear.  Apears to be it doesn't like to rev past 3500 rpm.  So should I test my TPS or does it have a rev limitor that could be at fault?  Thanks in advance!
-roman-

Answer
Hi Roman,
There is no rev limiter to the best of my knowledge. Testing the continuity of the tps is a good idea, measure resistance between the center and either side pin of the plug while you move the throttle.
Because it is an '89, you should be able to get the 'fault codes', which would give a clue as to what is wrong, by using your ignition key. Turn the key "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. By "on" I mean the normal "run" position of the key.
Then watch the check engine light to begin to flash, pause, flash, etc. Count the number of flashs before each pause, then repeat to be sure the count is accurate. Then group the numbers of flashs into pairs in the order of appearance. The last pair of flashs should be "55". That is because "55" is the code for "end of readout". Do this key test and write back with the two-digit numbers (or the flash counts in order) that you find and we'll see if that helps solve this one.
To get back to me use the "thank and rate" tab where there is a space for 'comments'. I will get your answer quickly that way.
Roland