engine revving in cycles
 

Hey all,
I think I know the answer to this one , but because the H2 could possibly be different animal to what I an experienced with I wanted to ask your opinion.

It seems that when I get into my rig and start her up the idle cycles in the rpms.
800-1000-800-1000-800-1000
Shortly after it is idling normal.
No codes when I scan then using the 327 scanner tool.

So I am wondering what you think....

(p.s. just started happening a few days ago)

Re: engine revving in cycles
 

anyone????

Re: engine revving in cycles
 

BUMP

Re: engine revving in cycles
 

What year of H2 do you have? If you have drive by wire throttle body it may just be a dirty throttle body bore and plate. Could also be leaking intake gaskets seeing its a dry intake it will suck in unmetered air(vacuum leak) until it warms up enough to seal the leak

Re: engine revving in cycles
 

Sweet Humtech is here!!

Ok, this is my info
2003 H2 with about 125,000 on the clock.
The cycles started a while back but no codes are shown

I have found out that it isnt a warm or cold engine issue now.
Basically I can come out the the truck, jump in, start it up, sometimes it will rev in cycles, sometimes it doesnt. One good push on the throttle and the cycling goes away.
I have done some research and believe that you are probably right about the throttle body needing cleaning.
Is there a specific chemical/ cleaner that you would suggest for this?
THANKS AGAIN!!