rough idle in gear 1990 mirage throttle position sensor or idle speed

Don't know about letting them settle. I'm pretty sure I put the front and rear in correctly. Could you elaborate on "letting them settle"? I put them in with the engine supported. The upper left and trams mount were re-replaced. Again it only vibrates in gear and when the engine is warm. When the engine is cool the vibration is normal/tolerable. Seems to worsen mostly with AC and brake. Thanks again.

For the front and rear mounts, the mounts should be installed correctly. Reversedly installing them would result in the mounts not getting the free movement required.

Always install and tighten the side mounts first. Next the rear and lastly the front mount.

$550 is a good price but if the vibration only occurs in gear, the idling speed could be too low.

So spent $$ on / and returned a complete engine - that did not solve the vibration problem (Rough idle in gear when engine is warm -does not vibrate when engine is cold- engine tries to run smooth but cant hold it - vibration is worse with load - but smooths out if I increase rpms). Back to square one. Any ideas? I really think it is an electircal - possibly wire problem. Car runs fine when cold but as it gets warmer the vibrations increase, in gear, and worsen with electrical load (AC / headlights, brakes, steering).

What is the idling speed when engine is warmed up?

650 - dealer set

650 is too low. The specified idling speed should be around 750.

Problem found / solved. Broken diaphragm in brake booster.

However after all repairs and adjustments car is now running a little rough at idle in park,(smooth in gear though :)) seems sluggish, non responsive on acceleration. Do you have a suggestion to get it all back to specs? Would the adjustments made to resolve the rough idle in gear need to be undone now that the booster vac problem is solved?

Thanks again.

You would need to go over what you have adjusted and readjust them if necessary.