I have a 1993 Eclipse with a 1.8 liter engine and auto trans. It is completely stock, no modifications of any kind. The car runs fine except the idle is a little rough. The engine idles at about 650 rpm. The problem with the idle is the engine acts as if it misses every now and then. Its not really all that bad, but it is noticeable. I guess you could say the idle stumbles a little.
I have checked the plugs, plug wires, ignition timing, timing belt and settings, idle control motor (it checks out good resistance wise and in moves smoothly and completely with 5 volts applied to it), the PCV valve is good, the throttle body has been cleaned and inspected, I have checked for vacuum leaks and found none (maybe Imissed something), there is no EGR valve, the distributor cap and rotor are new, I have tested the power transistor and coil in the distributor, the engine, head and tyranny all have been rebuilt approx 1,000 miles ago and I installed a new air filter. The balancing shaft belt is new and the shafts timing was adjusted when the engine was assembled. About the only thing I have not checked are the fuel injectors, the fuel pressure regulator and the fuel pump. But if any of these components are bad you would think it would display symptoms at all engine speeds.
Any suggestion would be greatly appreciated.

Thanks
Scott

 

How about adjusting the Valves on the cylinder head?

 

what about fuel filter

 

The car has hydrolic lifters, but I will check then anyways and I will also check the fuel filter.


Thanks
Scott