Gents,

I've trawled through the forum looking for an explanation of my engine issue, but without success. My car drives beautifully and only has 75,000 careful miles on the clock. If I park it for 20 minutes at the store, all is fine on the way home, but if i park it for an hour or so, then I get the amber poor engine performance and then the red engine fault warnings. After a few miles I the engine starts faltering, sometimes to the point where it has trouble maintaining speed on a hill. I leave it overnight and its perfectly fine the next day. If I am in bad traffic for some time, the same thing happens, even without a stop, so I'm thinking it has to be something breaking down when it gets hot. The cooling system has just been overhauled - new thermostat with alloy housing, pressure check is fine, etc.

I just had it in the shop to have the cam chains and tensioners done. They serviced the throttle body and fitted new plugs, so I was disappointed to find the problem still extant after considerable expense. The shop did clear a couple of codes - P1798 and P1227, but they are not a Jaguar shop so they are at a loss to know where to look next. I'd like to determine the likely cause of the problem if possible before throwing more money at it without any real idea where the problem lies.

 

Hi.

Judging from your description and code P1227, you have a problem with your mechanical guard in the throttle body.
Start with the cheap and easy. Disconnect and clean connector marked 1 at the throttle body and report back.
Code P1798 could be a result of the fist one.

You say they serviced the throttle body. What exactly did the do to it?

ALWAYS DISCONNECT BATTERY WHEN WORKING ON ELECTRICS

 

Thanks oyster, that makes perfect sense. I'll try to find time this weekend to do this and I'll report back here.

Cheers,

Ian