Intermittent Rough Idle 1990 Q45

[halfoffautoparts]

My '90 Q runs great usually. On occasion, it idles rough, usually in the morning. Other times thoughout the day it will continue and may be more pronouced as a miss on acceleration. Then, the next day, it will disappear.

[Jesda]

Could be just about anything.

This will just get you started:http://www.q45.org/roughidle.html

[halfoffautoparts]

I would like to do the fuel rail flush here at the house. Does anyone have the adapters or a source?

[Jesda]

I find Seafoam and throttle body cleaning to be most effective.

[Q45denver]

Sounds like one of your injectors are going out. If you've already tried the BG44K, I think the next thing I would do is ohm test them.

[DougQ45]

Also concur with the injector failure. Sometimes they are slow and cunning, other times absolute and complete. Check the resistance cold, and then hot, and chart it for a couple of weeks. You will then see which ones are failing. Watched an injector reading climb from 13 to 85 or so, during a 2 minute period just after shut off!!

[halfoffautoparts]

I have been using some Octane Booster and now that I think about it seems to correlate with the trouble. I think I'll quit that stuff.

Where is the easiest place to check the injectors?

[elwesso]

Check Q45.org for our INJECTOR OHMing writeup......