Troubleshooting a weird problem with my 8KM XJ220. I get the impression I’m the first person to drive this car, I mean actually drive it. Belt service, fuel cell, etc all up to date and a significant amount of maintenance ($100k+) performed by the prior owner. I’ve driven this one about 100 miles or so and started to have unusual performance problems.
Now, 5-6 minutes after start whether it’s driven or not, idling from start, it will repeat this behavior. The idle RPM drops, it begins misfiring and light throttle input results in amplification of the misfire - the engine revs slowly.
This is not correlating to boost, the engine has had none or little boost when it begins (this example in video is from start, idle, not moving the car or touching the accelerator). Note the tachometer swings around oddly with throttle input too - something funky here.
The car goes from idling smooth to a reduced idle that’s rough with some minor to major popping out of the exhaust. The mixture out of the pipes smells rich when this behavior occurs.
Here’s today’s example in video form showing the behavior at the dash and then with no throttle input from the rear of the car.
It starts, runs, idles and revs normally prior to 5-6 minutes of warm up time now. (For good measure I’ve turned my aftermarket boost controller down to 0 and 5% and see no variance.)
Video here: Misfire - YouTube
Anyone have any tips tricks or ideas on what might be driving this behavior?
Thanks in advance!