Hello all, haven't posted in years (was an active member since 1999) and yes, I still own both 1998 S70s.

Maybe someone can help or give some suggestions, my 1998 S70 GLT started to give a rough idle during a warm start (engine turned off for less than 30 minutes and started again). This happens 60% of the them.

My mechanic suggested I try putting fuel injection cleaner before doing more investigative work, which I did.

Now the rough idle would also happen when the car is idling. The CEL then sometimes comes on and then the rough idling disappears. The CEL later disappears that same day or the next day. Twice my mechanic was able to get the error codes when the CEL was lit and it read multiple misfires (I saw his scan tool readout but didn't write down the codes) but then the CEL later disappears.


The spark plugs are new, the cap and rotor were replaced less than 20,000 miles/4-yrs ago, and the MAF was just replaced with a new one (I replaced it myself with a BOSCH OEM part) hoping to eliminate one of the probable causes.

I have an appointment to bring it in next week and my mechanic is thinking of swapping the ECU to see of it is the ECU.

Any thoughts or suggestions?

Thanks in advance!
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Brian M. - 1998 S70GLT, 1998 S70 GTA