RPMs All Over - Up and Down

jandr1cj · #1 10-24-2012, 07:29 AM

Fired truck up this morning and drove to work. RPMs were fine at first, push in clutch and they would drop from running rpms (2-3000) to 1600-1800 RPMs and shift great. Once truck was warmed up, about 3-4 miles, I would push in clutch at a stop sign and RPMs would drop below 500 and jump back up to 1100 (back and forth about 2-3 times) before settling at 900-1000. Then I would take off from stop sign and shift from 1st to 2nd or 2nd to 3rd, rpms would drop from 2-3000 down to 500 and then when I would releash clutch they would jump back up to running rpms again but I am hearing a clunk when I release the clutch too. This all just started happening. I put a can of seafoam in about 2 weeks ago and another one in last night when I fist noticed this problem. Any ideas?

jandr1cj · #2 10-25-2012, 07:12 AM

Think I have found out what my problem is. Ideal Air Control Valve. I took it off last night after work and tried to clean it. The truck isnt surging on me and dropping down to 500 RPMs but now it is getting stuck at 2000 RPMs when idealing... Going to look into a new IAC and gasket and see if that works. Anyone else have this problem?

mazdadave · #3 11-02-2012, 02:58 PM

I had kind of the same thing. Ran good for a long time, one day it would not keep idling. Then it started idling at 2800.
Stopped at the parts store, and cleaned the MAF, been doing good ever since......
I want to clean the IAC now, is is hard to get to? (where is it?)

94mtx · #4 11-02-2012, 03:37 PM

It's attached to the throttle body on the back of it... It's like two 5.5mm bolts or some crazy number like that. there is a metric size that fits perfectly as well... Not the easiest thing in the world to wrench at, but it's about a 10-15 minute part swap... It's basically at the firewall on top of the valve cover.

There are two sensors. The TPS and the IAC in the TB. The IAC has a cylindrical shape to it and will be easy to identify.