has any seen a problem with an idle that moves up and down from 2 rpm to 1....back and forth over and over?

 

could be alot of things
1. Bad TPS (Throttle Positioing Sensor)
2. Vacuum Leak
3. Time to use sea foam worked for me.

 

what he said, check all your vaccum lines. sounds like a vaccum leak

 

is there a section in the service manual that helps with troubleshooting that type of problem cause i cant find one.

 

Check for a vacuum leak.

 

where would i start with that.....i am not too experianced with that.....is there a special tool i need

 

could brake booster vac hose cause a problem like that?

 

try the coolant level...low on antifreeze maybe...

 

low antifreeze would cause the car to move from 2 rpm 2 1 rpm back and forth quickly? I did pull the head.........

 

i cant text...but yeah...with it low you'd have air pockets that tricks the thermostat...im not saying its for sure your prob though

 

this a a very fast and rapid change in rpm.....still think that could do it?

 

if its the brake booster vac line you will here a load hiss, and its really hard to push in your brake peddle

 

well that is the only vac line that i can think of that is bad........this sucks.....i did the head gasket swap and now it is not idling right.....is there a spot in the service manual that tells about vac lines?

 

well if you just did your head gasket did you make sure your timing was at TDC? that might be your problem if its not a vac line

 

yes i made sure i was TDC on cylinder 1.....i aligned the crack pully to the white mark.....then i set the cam gears TDC...they where off by a hair only.....then i set dizzy......

 

You get the updated version, just added the ending.

High Idle speed and Fluctuation troubleshooting

Leaking EACV- Disconnect EACV connector. Idle speed should decrease. With the connector disconnected block the hole in the intake port or pinch the hose from the air cleaner to the EACV. If the idle speed decreases the valve is leaking. This condition will not set a code. The ECM can only detect an open or short circuit. It also may clog it’s screen if it has one.

Leaking IAC- (Idle air control valve) Disconnect IAC connector. Idle speed should decrease. With the connector disconnected, block the hole or pinch the hose to the IAC valve. If the idle speed decreases the valve is leaking. May not set a code and may not be a codeable circuit on all models.

TW or ECT sensor- (engine coolant temperature sensor) voltage should be about 3.0 volts @ 60 deg F and between .55 & .7 volts @ normal operating temp. If the voltage is above .8 volts at normal operating temp, will cause rich mixture and high idle speed. May not set a code because it is not far enough out of its operating parameters. **Also this sensor will not read temperature correctly if coolant is low. (beware)

Vacuum leaks- a loose vacuum hose or leaking intake manifold gasket can cause high idle speed and/or fluctuation. Also check for bad PCV valve.

Fast Idle Valve- (if equipped) a fast idle valve that is sticking can cause high idle speed and fluctuation. Check it by removing the steel cap on the top and putting your finger over the hole in the middle of the seat under the cap or block the port just inside of the throttle body opening, when the Idle is fluctuating or staying high. When the engine is warm this valve should be closed. You can tighten the seat but it will also change the idle speed warm up values (closing).

Throttle valve- throttle position sensor voltage should be .5 volts with the throttle closed. Make sure the throttle valve is fully closed and voltage is within spec.

ECU-If all else is good, if you reset the ECU and the problem goes away temporarily, the ECU may be defective.

The idle fluxes due to the fuel control programming built into the ECU, it notices that the engine is going too fast and that there is no VSS signal to the speedo, so the ECU cuts the fuel to the injectors to eliminate a higher than normal idle speed since the vehicle is not moving. Once the idle drops to a predetermined level the fuel injectors are turned back on and the vicious cycle starts all over again.