Hi All,

I picked up a 98 EX 5 speed w/128k miles on it. I recently had the timing belt/water pump changed. Then I did a valve adjustment (.008 intake .010 exhaust) following the DIYs I found. I also replaced the spark plugs, spark plug wires as well as cap and rotor. Well now after all that the car is idling rough when warmed up. After diriving for about 10 mins I will pull up to a stop light and it idles right around 600-650 rpm but is pretty rough. If you listen to the exhaust it keeps randomly sputtering (like hmmmmmmmmBLAP BLAPhmmmmm BLAP) The door panels wobble a little as well as the shifter and it can be felt throughout the car. It is not so rough that it is only running on 3 cylinders tho. I need some help trouble shooting this. Here is what I have done so far:

Checked timing marks on belt and cam - OK
Checked ignition timing and adjusted - OK
Rechecked valve clearances - OK
Tried swapping old cap and rotor/plug wires back on - No difference
Cleaned IACV - No difference (but had a lot of dirt on the screen)
Cleaned the TB - No difference

I have no check engine lights or anything. Any help would be really appreciated. The engine seems to run smooth all the rest of the time! Even when driving at night it will raise the RPMs to about 700-750 and run great under the added load. Also the idle DOES NOT HUNT. It just sits down there all rough like!

 

I had the same problem
What I did was :
1. Warm up the car until the fan kicks on
2. Disconnect the battery for 30 seconds
3. Connect it and turn on car with nothing turned on( no lights, ac radio) for 5 min.
4. Turn off the car, turn it back on and it should idle fine

 

The problem may be as simple as bad idle timing. Have you checked the idling screw and verified that it is set to proper value? If not then give it a try and you might end up solving the issue.