Help please! Need some assistance as to what and where to go next. 1998 XJ8 with code P1226, I went thru entire testing flow chart on this and came up with R&R throttle body assembly. This unit i did purchase and lucky for me the code immediately set itself again. The only symtoms that i have is during highway trips every 5 or ten minutes the car seems to have an erie feeling like someone shut off the fuel flow, but it still continues at the same speed then you will feel it return an minute or two later, during this you cannot accelerate, you can ony continue at that speed and wait. Any help would be graet. Thanks

 

Quick suggestion - unplug and replug the Throttle Position Sensor connector several times... if your's has the tin pins in the harness and gold pins in the TPS body, galvanic corrosion can cause bad connection/mis read by the ECM. Unplugging/replugging several times will wipe some of the corrosion away.

If this seems to fix it (or change the behavior), then a good cleaning with connector cleaner/lubricant as from Radio Shack will give you some long term peace of mind; replacing the tin connector pins with gold (as suggested in a Jag TSB) should be a permanant fix.

 

Try what Quadman said but you might need to find an intermittant connector fault somewhere in the harness between the ECM and the throttle. Hard faults are easier to find than intermittant ones because a short or open remains constant but intemittant connections are illusive!!

See DTC guide .pdf attachment.

bob gauff