Photojared

Hey guys,

I've been dealing with this for a long time. My XJ stutters and backfires then runs "fine" after. It still has some hesitation from starts.

As of right now my XJ is throwing 4 codes.

P0300 - random/multiple misfire detected
P0303 - cylinder 3 misfire
P0304 - cylinder 4 misfire
P0122 - Throttle/pedal position sensor/switch "A" circuit low

What I've replaced so far:
TPS (twice)
Injectors
Cap
Rotor
Spark plugs
Upstream O2 sensor
CPS
Ignition coil
Catalytic converter
Exhaust
Header

I can't figure out for the life of me what is going wrong. Compression checks out (a cylinders within 5-10%). I'm going to check again to make sure. I've also verified fuel pressure at the rail. No problems there.

I've also inspected the wiring harness following the TPS wires back behind the valve cover with no pinched wires or shorts.

Unfortunately my smog is due very soon and still can't figure this out.

Please any suggestions help.