XJ6 & XJ12 Series I, II & III 1968-1992

Throttle hesitation

Old 05-25-2008, 06:39 PM
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Default RE: Throttle hesitation

the AFM and AAV come to mind as possible culprits. The AFM specifically, the black electronic box after the air filter canister.There is a fix located at Jag-Lovers which entailssoldering a resistor to the AFM's circuit board. I believe this fix came about for the 1986 and 1987 model years.

I am not saying THAT is the problem, but is a potential answer, based on what I have read from others withsimilar symptoms.You'll need to register there to access thefix, and while you're at it, you can also ask the question at the XJ forum. Not trying to steer you away from here, because I also like this forum, but inissues like this, the answer is already at Jag-Lovers.

let us know what you found out. BTW, my first car wasa 1969MG-B built in 1968. Brand new!

I still have the Steering Wheel, Owner's Manual, Passport To Service booklet, and Dealer Brochure!

Old 05-27-2008, 01:47 PM
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Default RE: Throttle hesitation

Greetings Kristian,

Series III cars almost never have throttle body problems. The ignition coils on '86-'87 cars fail more often than the previous models, and can cause this symptom. See if the coil tower is wet, that confirms leakage of the oil inside it. You can use just about any 12v coil to test by substitution...but if you replace the coil, you must obtain the proper coil with the external ballast resistor. Of course there could be many other causes: the Air Flow Meter is one, the Auxilliary Air Valve is not. Aside from inspecting the coil, you should have a look at the cap and rotor.
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