Trying to find an Interchange part # to replace my amplifier on a 1992 xj6 4.0.Understand they only have a 5 year 50,000 mile warranty, I'm at 150,000. Have seen interchange #'s for series 3 XJ's to a GM amp but not for XJ40.
Have a pesky "miss" I can't seem to find the cause of.
Compression good in all cylinders . Cam timing spot on. Have installed a new ignition wire set, plugs,(Rotor and cap have 1,500 miles). Have cleared all codes; last was EGR switching valve. Runs great under acceleration, still missing and "lurching" at steady 2000 rpms. All vacuum lines look good. Vacuum test appear within range, except for irregular 1" inch drop looking like ignition miss. "Feels" like a ignition miss, not fuel.
Had a problem initially with a new rotor. Would not run at all, until I replaced with a different brand. Then it ran but had severe arcing at coil (also new and within specs) until I replaced plug wire set. Have not replaced Oxy sensor yet, trying to test. Don't have much hair left to pull out, all suggestions appreciated.

Shelby:
Is this what you're looking for?
http://jaguar-parts.jagbits.com/sear...page=1&filters[catcode]=XJ40_EngineElec_12&sort=code%20asc

Scott

Ooops, sorry that link did not work for some reason. Go to Jagbits, XJ40, Engine Electrical, Ignition module...

Scott

You may also want to check the throttle position sensor. It can start to give erratic signals and symptoms similiar to yours. And from what I have read here on the forum the sensor can be cleaned if necessary to improve a signal issue. Cary

Checked Voltage signal while slowly opening throttle; found "dead spot" where voltage did not smoothly increase to wide open value. Replaced with one from donor car. Now signal gives smooth transition from idle to WOT values, but I still have "missing" symptoms at steady 55 MPH , or lower gears at 1800-2000 rpms. Going to replace Amplifier next.

Are you using aftermarket wires? The coil wire from aftermarket sets seems to back it's way out from the coil, from my experience. What do your plugs look like?

Turn off the lights in your garage and get a spray bottle of water, spray it around every electrical component in the engine bay, look for arching.

The little capacitor connected to the sill plate is also suspect. There are several grounds down there within that ignition section, they may need a good cleaning.

Pull out your CPS and clean it as well.