I had a CHECK ENGINE LIGHT lit once last January of this year and found that I have codes P1310 for ignition coil 3 primary feedback circuit and code P0300 for random/multiple cylinder misfire detected.

The first step I did was to check the oil level and found that I have none left. Quite odd to realize that it consumed that much oil after 3k of usage knowing that I never experience this car to consume that much oil.

Second was to pullout codes and evidently got these codes w/c was mentioned on the 1st paragraph.

The steps I've done during that time was to;

***change the oil - Mobil W10-30 synthetic
***change my plugs from NGK back to Genuine Volvo T-5 plugs
***reset the codes

After these steps, CHECK ENGINE LIGHT never returned.

I have been battling for a year now of the HAUNTING IDLE and HESITATION.

Replaced TONS of parts already and next project to replace and do this week are:

***TPS switch, clean TB, ECT sensor, fuel regulator, upper engine mount and knock sensors.

You can reference the tons of parts I've replaced through the subject MECHANIC GAVE-UP TO SOLVE ROUGH IDLE on JULY of 2003, anyway I'm not going to let you do that work, I'll list them for you guys to see what I've replaced;

- bosch ignition wires then back to volvo bougicord ignition wires
- ngk pfr6 spark plugs then back to oem volvo
- bosch distributor
- bosch rotor
- super coil upgrade
- bosch fuel filter
- bosch o2 sensors
- maf sensor
- air hose
- k&n filter
- change vacuum hoses/elbow
- driving selector switch
- idle motor
-*car has no EGR
- 5 bosch fuel injectors
- front engine mount


Whew! I guess that's all folks and thanks for your inputs.