Originally Posted by ackmed42
i installed a spectre air filter in my 2003 3.0 flex ranger a day later the CEL light started flashing now its on constant code is misfire cylinder # 4 could it be the flex motor does not like the added air flow
Highly doubtful. Probably just a coincidence. Our local Kmart/Sears stocks Spectra brand air filters, and I have replaced my OEM with one. When was the last time you had a tune-up? That would probably be a much needed service.