Subject: auto repair
Question: I have a 1991 eclipse with a 1.8 engine.My problem is that the timing
belt  was recently replaced .My car now has the following symptoms.loss of
power,loud engine and the car vibrates[steering wheel]. i have had the
vehicle looked at and the mechanic can find nothing wrong. i am
frustrated with this problem...the 'tps" sensor was replaced but no change in the
problem occured. what could be the problem. I need suggestions.
I do not know what to do.......thank you..al
Answer: Check your spark plugs, plug wires, distributor, and PCV valve. You may have an ignition problem, and the symptoms you describe sound like it. You may also have a timing problem. Your intake speed control motor may be faulty.

If your mechanic is completely baffled, you should have your car's computer checked out. Read this web page for some more information for the reason why I mention your car's computer:
http://90gsx.com/eclipse/cap/caps.htm

If your computer is failing, the problem you described is quite typical. Your ECU may need to be replaced.
Good luck!