weird idle

in the morning i usually let my truck warm up for about 5 min. sometimes ive noticed it will just be idling and it will rev up and down up and down by itself and will keep doing this till i drive it(morning). then sometimes after skewl i start it and let it warm up 30 sec and then five min. later at a stop light it will start doin this and then stops once i start driving. it doesn't go down till its about to shut off but it revs up and down quite a bit.

anyone know whats going on??

o ya i have no cat if this matters.

FI or carb?BJ

I would check the choke.... Or the EGR Valve.. I had and older mazda that did that and it was the EGR .. I took it Of and Cleaned it with Carb cleaner and it never gave me a problem after that .. But It can be something else but thats were Id start... (Mazda RX2000)

its FI and that is what it seems to me is that it was the choke. so like you said all i have to do is clean it up and see if it works>??

it could also be a vaccuum leak inbetween the massairflow sensor and the throttlebody that common on fi motors

thanks for the ideas and ill start with the choke and work my way around untill i find the problem.

sounds like a vacuum leak to me. its a good idea to replace them as old as these things are anyways. if you to your local parts store there is a silicone hose kit you can buy for like 20 bucks that has the sizes you need and will never crack. they will be there when the truck is dead. pull hose off one at a time and cut the length you need and replace until all have been done. you can get different colors too.




-justin