First post - glad I found this awesome forum! Trying to learn this car.

Bought a "first car" 1990 LX w/AT for the daughter. $1500. The car has pretty high miles (190K), but doesn't burn a drop of oil and is very clean and straight. It had pretty good pep at highway speeds but seemed to be getting only 19-20. Other "problems":

Clunked into gear when shifting into any forward or R gears.
Has an annoying rapid "jud-jud-jud-jud......." just off idle when moving from a stop. Engine seems to momentarily lose power to the ground. BUT only is noticeable when car is warm. Hard to tell if root cause is injectors, electrical, AT, other...

So I ran some high doses of FI cleaner through, changed the shot front motor mount (from Bernardi), flushed the tranny completely with synthetic Dex III. New motor mount eliminated the clunk (duh), car goes much better and MPG popped to 25 mpg. I'm thinking victory - but the "judder" and miss still seem to be there when warm.

Anyone experience this before? Help?!?

 

No experts on this forum to take a crack at this one?

Not a common problem I guess. I'll get a manual and see what I can do before I have to find a shop. (yikes)

 

see if there are any codes stored. my 93 got 143 miles n 9.5 gallons of 93! found a code 5 for map senso. gonna try that and see if it helps

 

Don't know how to check codes on a 90

 

pull up the carpet on the passenger floor to look at the computer. count how many times the red light on the ecu blinks make sure the key is in the on position

 

Have you changed the spark plugs and air filter yet?

 

I would look for the normal things which would cause a cylinder to drop out under load; a vacuum hose leak to the intake manifold, a sooted or improperly gapped spark plug etc. Even a dirty Throttle Body could contribute to this.

If you notice this around 1800 to 2000 rpm under light load in 4th gear range, you may have some carbon buildup in the EGR distribution manifold. This distributes inert Exhaust Gasses to the cylinders to control Al Gore Gas. If several of these ports should clog, an excess amount of inert gas would be fed to the remaining cylinders; decreasing their performance, thus the judder (skip).
Although it happens with some regularity around here, I would consider this once everything else is checked first.

P