Had car run rough on startup a few times, one time a strong gas smell in the cabin. Sometimes would go into restricted performance, but simply turning off and restarting the car would clear it. Car runs fine when warm.

Throws the usual P1000 P1642 plus the new P1144.

Found this: Code p1144 wont leave me alone on XK8

Suspect that the AACV failed to open, an effect of which was to mess up the mixture causing the rough idle? Because of the gas smell I'm guessing way too rich. I can see some gas at the bottom on the throttle body, don't know if that is normal or not- would not be normal for other cars I've had. Would an AACV malfunction cause fuel overflow?

I'm familiar with a bad idle air control valve causing a hunting idle, is this a similar function for the AACV or a different function?

I removed all the electrical connectors to the throttle body and MAF and cleaned them with electrical cleaner (spray). I also cleaned the throttle bosy and the MAF with carb cleaner. Haven't tried to start it yet.

Research suggests replacing the entire throttle body.

Opinions on rebuild versus used part?

Comments and suggestions? Thanks.

 

Check the full load breather pipe that runs from the left side valve cover to the base of the throtal body for leaks. It may be leaking just after it leaves the valve cover, it so this may be your problem. It is an inexpensive part and you can use duct tape as a temp fix. If you have a code reader see if you are gettting a "lean" report on both banks.
LaRue

 

I'm pretty sure the entire plastic intake tube was replaced about 14 months ago. I'll check the breather tube again. I did disconnect and reconnect the breather tube at the valve cover.

Air entering downstream from the MAF will definitely cause mixture problems and rough running, but does that explain that it runs well once warmed up? I seem to recall reading somewhere that the AACV is open while cold and closes when warm, which made me suspect it more.

Thanks,

 

Sounds like the symptoms I dealt with. Once car was warm, ran great until I hit full throttle, then was fuel starved.

 

Update: Swapping in a rebuilt throttle body seems to have fixed this problem.