Intermittent misfire 1994 Q45a

[morton27]

I reposted this here from the general infiniti post to get more replies, hopefully.--------------------------------------------------------------------------------

My 1994 Infiniti Q45 has an intermittent misfire at start-up. I plan to check plugs and injectors any other ideas? Car has 168,00 miles.

[maxnix]

And a summary of the recent maintenance history is?

A power balance test will tell you a lot.

[Desmoquattro]

Start with cleaning the MAF, the throttle body, and REPLACING the spark plugs (checking is never worth it, especially on the Q which takes so much labour to do. And usually it's hard to tell when a platinum tip plug is toast, unlike a copper core plug). Simple stuff first. Then do the easy injector / knock sensor resistance test outlined here:http://www.q45.org/ohminjectors.html

Mine ran quite badly when cold when I first got it, and stalled a lot. The guy who sold it was afraid it was a fuel injector that had gone bad (he had already replaced a couple, as well as the O2 sensors and the knock sensors). After cleaning the MAF, putting in a new air filter, cleaning the throttle butterfly, and replacing all the plugs, it starts and runs beautifully even in -10 C weather.