I have a 89 xjs with a lucas ignition system and when i start the car it idles up fine at first but then right as it comes off cold it starts pulsating from 1000-1700 rpms, but if I hold the gas slightly it revs up just above 1700 and holds. I thought it was a vaccum problem but all leaks have been fixed..that i could find. I also took the idle control valve off (not sure if its the right name), the one that connects to the water port with the idle adjustment screw in it, and cleaned it. Any suggestions??? Also off topic is there only two kickdown switches on the car...one one the potentiometer and cable...or is there another??

 

Yeah I'm quite sure that the linkages are sync'd, don't think they have ever been adjusted...but will check to be sure, but didn't know about the throttle gap...but that will be checked here shortly also, bad weather right now. The aux air valve....didn't seem to be leaking anywhere...checked the vac hose coming out and lines leading from that....the throttle bodies have both been off and rtv'd to make sure they were sealed and the bolts are tight....is there anyway to test the aux air valve....the only thing I could think of was testing it like a thermostat in hot water, but wasn't sure...outside of warming up the car runs great...and yeah its the kickdown switch that is busted....had me confused until I looked into it...I didn't know that they used the same micro-switch for the overrun and kickdown...what suggestions do you have for that one....actually found the switch through CarQuest....

I also noticed that the supplementary air valve that goes into the passager side air box is fitting snug...could that cause some problems....and how can I test that as well

any suggestions on a good website with vac diagrams just so I can be sure everything is were it needs to be