revving up, surging forward

[nesta]

When my Protoge, 1999, 1.6, lx, is warmed up and I am in stop and go traffic, the engine revs up and won't operate normally; it surges forward even with my foot on the brakes. If it's not hot, 70+F, this does not happen. The rest of the time it is fine.

Any thoughts you fine folks can offer?

Thanks!

 

[nesta]

hmmm when i have this problem its usually...

idle air control valve / MAF sensor needs cleaning or replacement,
or idling control on the throttle body needs adjustment.

does the idling just go higher at random intervals or does it also dip to the point of near stalling?
also does using the A/C affect the issue if at all.

I will check the MAF, which I think is the same thing as "air control valve"?

The idling ramps up at times, real high, and will dip but revving will continue.

Yes, this tends to happen more often with the ac on.

And if, as it revs, I put it on park (it's automatic) it ramps/revs up even higher.

 

[nesta]

hmmm i see.

the idle air control valve is the one attached to the side of your throttle body.
its moderately difficult to pry open especially if its old, and can get dirty quick.

!

I ran off after the last post to go look for the idle air control valve but can't yet find it. Still looking...

MAF sensor is much easier to check, its located along your stock intake just after the filter box.
a square 1 by 1 inch sensor housed by 2 screws, if you remove the screws you can clean the sensor inside, it hangs like a roof lamp.

I found the MAF sensor and cleaning now with rubbing alcohol.

be sure to adjust that little sproket on the side of the TB, it looks like a knob and is solely for idling adjustment.

Please let me know which sprocket you're talking about, and what's the TB and how I adjust it; up/down etc?

am automatic and 1.6L as well and have this issue every now and again.

from the symptoms it seems to me like dirt is in either of those sensors or the EGR valve, causing the wrong idling information to be delivered.

What's the EGR valve; where can I find it?
when this happens more often with the A/C on, it shows a lack of inability to cope with extra load on the system.

if problems persist beyond checking the 3 components, it could be caused by something more advanced although unlikely since there is no check engine light.

do keep us updated man, and welcome to the forums![/QUOTE]

I want to THANK YOU!!!! very much for all your help this far. Off to check on the MAF. Thanks a million!