Toyota Repair: Uneven acceleration, valve cover gasket, toyota celica

Question
Hello,

For a few weeks now I seem to have been having a problem with my car.

When I am driving, the power seems to be variable. That is, when holding the gas pedal steady or accelerating the power seems to come in bursts: it surges then hesitates then surges and hesitates again. This cycle repeats approximately once or twice per second. It does this about 30% of the time. It is more noticeable at low/intermediate speeds, but it does it at highway speeds as well. The surging is quite clear but reasonably subtle.

In addition, it seems to have less power overall than it used to. By power, I mean acceleration in response to stepping on the gas. A few weeks before it started having this lack of power problem the car seemed to have the opposite problem. That is, it had more power than expected when I stepped on the gas.

Basic Info:
1990 Toyota Celica GT
Automatic transmission
~120,000 miles

Repairs:
About two years and 5000 miles ago, long before this surging problem started, I had some repairs done at the Toyota dealer:

(1) Replaced ignition system components and spark plugs
(2) Performed BGEFI Service
(3) Replaced valve cover gasket
(4) Replaced distributor O-ring
(5) Replaced front motor mount

Any help you could give me would be much appreciated.
Thank you,
David


Answer
There are a few things to check, make sure there are no leaks on the intake system, check the intake hose for looseness or cracks,check the ignition coil in the distributor, they have a tendency to develop cracks and arc
through the insulation, check it carefully with a light especially on the bottom, you may have to remove the rotor and a plastic cover, also, but not as common, the fuel filter may need replacing and check the air filter and the intake hose for any foreign objects.