My 95 Disco has started having a problem where, on startup, there is about a ~30% chance that the truck will idle below 500rpm, stumble and shake and refuse to rev up when the gas is depressed. This sorts itself out after 30 seconds or so, but it has been getting worse and more frequent. I'm afraid I'll have a no start soon.

I do have a code 12, but disconnecting the AFM during an episode made no difference.

Some other details - 215k miles, unknown tuneup condition, plan to do this soon. Air filter and fuel pump have been replaced recently. No coolant loss.

Any help is appreciated.