My idle is gradually climbing , last week around
2000, today 3000 . .
I had the fuel pump replaced and was fine for several months afterwards. I replaced the valve cover gasket today because oil was leaking into the spark plug holes and onto the exhaust.
i thought is was the source of smoke on the left side of the engine compartment, but now I'm wondering if these issues are connected.
Any thought before I take it into the shop ?
Just too busy at workato dig into it any more myself.
thanks

 

the throttle body on the xj6 is a poor design with the throttle shaft running north and south. Most now run east west. This becomes a problem as oil gets into the shaft at the bottom, that and blade buildup makes the throttle stick and not return. The fix is cleaned the throttle body and take the top of the spring tower off and wind the throttle return spring 1 turn tighter and reinstall.
This usually fixes the issue unless something else

 

There are a variety of threads on this subject, including my own. To cut a long story short, my XJR high idle problem was caused by a worn throttle position sensor. There are a variety of relatively simple things to check first, most notably in my opinion the adjustment of BOTH parts of the throttle cable, but it all came down to the throttle position sensor in my case. It is a pain to access it on the XJR, as the throttle body is obscured by the intercooler under the inlet manifold. Inlet manifold removal is a serious PITA, and the recommended method for removal of the throttle body is from underneath after removing the oil filter. Access to a lift strikes me as essential for this approach, but maybe it is possible on axle stands if you have long arms! Be sure to familiarise yourself with the water hose connections to the throttle body, the attachment of the throttle cable, and the electrical connectors to the ISCV and the TPS.
The removal of the inlet manifold route takes a lot longer, and in complicated by the need to disconnect a number ( 7 or 8?) of connectors below the manifold to allow the wiring loom to be removed from between the branches of the manifold. Sounds easy, but access very restricted. You might be able to move the manifold enough to access the throttle body without disconnecting them, but it is very tight.
Read the threads for the full story.
PS the throttle body on the normally aspirated cars is easily accessible .

 

I bought a used TPS for my 95 XJR but before I went to the hassle of removing everything I did some easier jobs first.
Replaced the coolant temperature sensor (CTS); made it a bit better.
Removed and cleaned the mass airflow meter (MAF); made it a little bit better.
Replaced the crank position sensor (CPS); fixed it!
And i now have a spare TPS just in case that goes haywire.