1993 940 new plugs, wires, cap and rotor button but idle is still rough? Car runs like a top but the idle is not smooth. Where should I look next? Any help is greatly appreciated!

 

Clean the throttle body and idle motor.

 

I cleaned the throttle body but where is the idle motor located? How/what do you clean on it? Thanks in advance!

 

It is a cylinder looking thing mounted under the intake manifold.
It has 2 hoses going to it.
Clean it with either Carb. cleaner or Brakeclean.

 

Do you remove it to clean it?

 

Also what brand spark plugs and what gap should I be running in this Volvo?

 

Yes you remove it to clean it. After you clean it spray a dab of WD-40 in it and try to work it some.

I perfer Volvo plugs But Bosch work good Gapped at .30

 

When you say "try to work it some" what exactly do you mean? I removed and cleaned it and put some WD40 on it and now the idle surges up and down from about 1500 to 2000 rpm's. What else can I do to it to make it function correctly? Thanks in advance!

 

I meant when you had it out.

Have you messed with the idle screw at all?
Are you sure all the hoses are back on good?

 

check the accordian looking hose that runs froml the air mass sensor to the throttle body sometimes these get a hole rubbed in them allowing unmetered air in. You can wrap with electrical tape as a very temporary fix if you have a hole. Replace accordian looking hose. The orings sometimes go bad around the injectors, when this happens you get a rought idle at first and then it smooths out as the car warms up.

 

did anyone ever determine the cause of this issue? Mine is having the same problem, runs fine, idles roughly. Car has new plugs, wires, and has 220,000 miles. I have checked the EGR, checks ok. Checked compression, checked ok. have checked injectors, they seem ok, as do the rings around them. I even checked the idle tensioner, nothing. Any thoughts on this?