For the past month or so my Capri has exhibited odd idle behavior, though only upon initial cold start-up like in the mornings. Here's what it does:
The car is cranked up and it immediately "stutters" and stumbles (like it's only running on 3 Cylinders) then shuts off. It's then cranked back up, at which time it will idle high softly up to 3,000RPMs then softly float back down to 1,000RPMs and stutter a little while around 900-1,000RPM then gently float back up to 3,000RPMs then softly come back down to ~1,000RPMs, back and forth etc. etc. until it finally settles smoothly at about a 1,000RPM idle. The exhaust note, after warm-up, etc. around 1,000RPMs sounds a bit "gurgly" or "throatish." It once sounded that way years ago and a new set of plugs took care of the problem. The car does not smoke at all when it "acts up" like this. Once the car is warm it idles fine and drives great...exhaust sounds really cool and "throaty" though...like an old Jag "gurgle." Normally it sounds very lame and uncool like a Honda Civic etc.
The thing is, I'm stumped...within the last 500 miles, as regular maintenance, I've replaced the following parts:
-Fuel Filter (Made in Japan)
-Air Filter (CarQuest)
-Battery (CarQuest 60 Made in USA)
-Distributor Cap and Rotor (Both Made in Japan)
-Sparkplugs (NGK BKR6ES-11)
-Valve Cover Gasket/Grommets (Made in Japan)
Any ideas?
The plug wires do not seem to be damaged anywhere...they pass the "water spray" test, etc. and conduct fine. Think I should replace them? If so, what's the highest quality source/brand? I don't like playing the game "let's replace everything and see"...I like to diagnose and pinpoint the problem, then replace the problem.
Anybody out there ever experienced something along these lines at the 159,000 mile mark?
The distributor was replaced at ~115,000 miles.
Any help would be greatly appreciated!