Having a problem with my Prelude '88 EX-I 4WS. A stumbling/misfiring problem has developed in the last month and seems to be getting worse. Under light acceleration when the car is fully warmed up the car seems to misfire violently. If I let off the gas the problem goes away only to return at another irritating time. It is very random. Aslo car has trouble starting sometimes when shut off after being run for a while. Check engine light also comes on sometimes but no codes present. Can take a while to get started again. Have replaced plugs, wires, cap and rotor so far but don't know what else it could be. Maybe timing? Maybe fuel filter? Maybe coil? Any advice would help getting very worried. Thx.

 

Could be EGR valve. I'm sort of haveing the same problem. But my timing belt was replaced and head rebuilt. One guy said sounds like the valves are bent; but I don't think your problem is that serious. Maybe one of your injectors is not spraying.

 

Valves are clicking fine (used a screwdriver as a stethoscope). Won't be bent valves as that would be a consistant problem. This happens every so often. Very strange. Occaisonal backfiring too on downshift at mid revs. Again every so often. And only when its warm. Still baffled. EGR valve is free and clear. Operates fine when car is turned on. Vacuum pulls it all the way back. PCV maybe?

 

Perhaps plugs or wires...?