Frankly I've been using 87 Octane gas which is regular. I hardly use this car only 24,000 miles since 2001 (S430). I haven't work on this car yet since it was under warranty until last April. I started getting this EPC malfunction several months ago but was intermittent and it ereases itself. I am going to start with the vacuum leak test and cleaning the MAF. Is there one MAF or two.

Thanks Michael for your time and sharing your knowledge.

Darrel