After receiving help from this forum I was finally able to get my 87 Xj6 running and driving. Upon its first drive in over a year, after sitting for about 10 before it broke down, I have a few issues I wanna try to resolve. First is that the car idles at 1100-1300 rpms, I was wondering what I could do to help this. Also, the throttle seems to stick a little, it wont let accelerate when I let off the gas, but it wont lower RPMs either, almost as if its in cruise control. Once I use the brakes itll drop after a few seconds but I can tell it still wants to keep going when stopped. It also seems to have a pretty rough idle but doesnt stall. Any help would be great!

 

The "could be" list might get a little long. A couple thoughts:

I'd begin by cleaning the throttle body and making sure the throttle blade is properly set at .002".

The throttle cables on these cars are known to stick. Disconnect it and operate by hand. Does it feel smooth and easy? Or tight? There's a nylon inner lining that will melt if the engine isn't properly grounded....because the cable itself become the ground path and gets hot.

Rough idle....

How rough is rough? A bit of a "tremble" is common....and often cannot be resolved. Many have tried to get a glass smooth idle with no success.

That said....

Check the flexible air inlet duct at the throttle body. Secure, no splits?

Dirty injectors can cause a rough idle, as can leaky injector seals.

Cheers
DD

 

The idle isnt too terrible, I know these cars never idle perfectly smooth, it just seems to idle a little high but I will definitely check out the cable as I am almost certain that it will need to be replaced, as even when I step on the gas it seems to struggle a little at first to speed up (feels stiff and unresponsive). The injector seals looked fine when I pulled them but I will double check. Thank you for the tips! Cheers!

 

the throttle cable in not available new, make sure you don't damage the one already in the car. You might find a good used one.

check the vinyl bellows from the air filter to the intake for cracks, particularly the ones before and after the AFM. Check all rubber vacuum hoses for deterioration.

make sure the Cruise Control switch is in the OFF position (the switch below the shifter).

 

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Series III Accelerator cable. help!

A new cable is not an "impossible dream"
Cheers

 

High idle, slow to return to idle sounds like lean mixture symptoms, check for air leaks. A can of spray carb cleaner sprayed around gaskets, boots and hoses while idling can help detect. I'd do this first before changing parts or turning screws. Check hose to vacuum booster.

 

Throttle return springs going home?