1995 XJ6, US model (air pump and all that stuff). The car had a history of stalling and running poorly that was cured approximately a year ago by installing 6 brand new coils (Diamond, made in Japan, good stuff, bought from SNG Barratt).

The car threw the air pump code before, I replaced the air pump with a used unit. I was told that it was a working unit, and it appeared to be making noises as if it were indeed working.

I replaced two oxygen sensors approximately a year ago. IIRC these were both downstream sensors (the ones that are closer to the tailpipe). P0158 is "bank 2 sensor 2", which is cylinders 4,5,6 downstream?

I have full IDS/VCM setup, so I should be able to perform any diagnostics. Where should I start digging? Is it possible to pull the fuel trims in IDS, and if so - how? I find IDS user interface less than intuitive to navigate.

 

Juha,

Any new insight with IDS diagnostics?

See Tcasmarcus' recent thread about his poor idle and stalling issues. A used MAF seems to have solved his problems, for the most part. Though we all know that the list of causes can be long:

Bad MAF
Bad old coils/New Aftermarket coils
Old/undesirable spark plugs
Old Crankshaft Position Sensor
Old O2 sensors
Dirty EGR valve
Dirty/Oily throttle body
Dirty/Bad throttle position sensor
Dirty/Bad Idle Air Control valve
Air Intake leaks
Contaminated fuel
Dirty fuel filter
Bad fuel pump
Bad fuel pressure regulator
Clogged fuel injectors
Corroded ECU terminal connectors
Loose/Corroded contacts and ground points
Bad relays
Low transmission fluid

There are more possible causes I'm sure.

We must eliminate the dirtiness and the badness!

Old spark plugs, contaminated fuel and the CKPS have been my real causes of stalling.

Seems as if all these issues are sorted, the engine should run perfectly!? Check off of your list the ones you've already attended to.