What causes the RPM to fluctuate at idle?

What causes the RPM to fluctuate at idle?

The anomaly was a fluctuating RPM gauge upon idle, the truck would start normally but would pulse downwards for a instant and then resume to normal. The fluctuation would occur during warm and cold days and even after the car had sufficient time to properly warm up.

When to idle air control at 1000 rpm?

Idle air control..it should idle at 1000 rpm’s when the engine rpm’s jump up and down,suspect the iac. Thanks for contributing an answer to Motor Vehicle Maintenance & Repair Stack Exchange!

When does idle come back to normal on a Harley Davidson?

Just seems to happen when I’ve been running at a fairly wide open throttle maintaining higher speeds for a while (fwy) or longer stints (catching all green lights) on the streets at a speed of about 45 or more. It always seems to come back to a normal idle after getting back into first gear when stopped, or when I start going again in 1st.

What should the idle speed be when holding the brakes?

You brake system relies on vacuum and an idle speed that is affected by holding the brakes probably has a weak vacuum. You can get a cheap gauge at an auto part place that will quickly tell you if you are in spec. Idle air control..it should idle at 1000 rpm’s when the engine rpm’s jump up and down,suspect the iac.

How often does engine RPM drop when idle?

The engine stays idling at about 1000 RPM. However every now and then it drops down to about 500 RPM and then quickly back up to about 1200 then goes slowly down to 1000 and stays there for a bit until I go again or it drops again. It only happens for a second or two and about 3 times a minute.

What causes the idle speed to fluctuate?

A leak will cause fluctuating idle speed. If no vacuum leak is found, then my next suspect would be the Idle Air Control (IAC). Are you saying that this started happening after you replaced the throttle body gasket?

What are the idle RPMs of a VX?

As I approach a stop and coast while in gear, I put it in neutral around 1200 to 1500 rpm, it settles to 1k or so and I get a surge of about 200 rpm as I roll to a stop, once at a complete stop the idle settles down to a perfect VX idle around 800 than as a VX will do after about 2 or 3 minutes it settles to about 600.

You brake system relies on vacuum and an idle speed that is affected by holding the brakes probably has a weak vacuum. You can get a cheap gauge at an auto part place that will quickly tell you if you are in spec. Idle air control..it should idle at 1000 rpm’s when the engine rpm’s jump up and down,suspect the iac.