My 2000 Z3 2.8 generally runs smoothly here where I live at the beach in SC, but on a trip west the engine started skipping and the higher the altitude, the more it skipped, especially if I accellerated in at lower rpm in a higher, so I stopped lugging, but the skipping reappeared occassionally. Now back at home the skipping is gone, but the engine has started running rough briefly when it is first cranked, then it smooths out. What could cause this? The engine has 68,000 miles on it, original plugs and oxy sensors, synthetic oil and filter every 7,000mi HELP. Thanks Darrel
68,000 miles on your ORIGINAL plugs and Oxygen sensors? That might be your problem right there. Those should have been changed about 18,000 miles ago. Have you checked for trouble codes? cracked (vaccuum) hoses etc?
Might also check the air intake tube, I had similar symptoms on my '99 Z3 and found the intake tube had a large crack in it on the under side (connects directly to the mass airflow sensor). Replaced mine ($20 or so at ECS Tuning) and it runs like a champ!
The O2 sensors are probably fine, but I'd definitely change the plugs and check the intake boots (there are two and the lower ones are harder to check and replace.)
Actually, the O2 sensor should be good for about 100k and the plugs should be somewhere in the upper mileage neighborhood as well...
They claim the plugs last to 90k but I have never seen a set lst that long without being in desperate need of replacement. I still do them every 30k.
