94 E420 high idle cold than

[sthomen]

What is this problem, high idle,1300, than warms up it fluctuates 1300-800 every second

All I did is put good gas, than I noticed it. all vac lines look good, I have no check engine lite on.

[eric242340]

You do not give much information or history to this problem but the biggest cause of this is a vacuum leak.

[sthomen]

All vac is good

[eric242340]

Originally Posted by sthomen

All vac is good

How did you test for vacuum leaks?

[sthomen]

Eyes, and ears. Is there a other way.

[eric242340]

Get a can of carb cleaner spray and start the engine from cold and spray small amounts over the vacuum area's such as manifold gaskets/vacuum pipes/fuel injectors etc and if there is a leak you will see and hear the difference straight away. Be careful not to spray this onto an hot exhaust as it is flamable.

[sthomen]

Originally Posted by eric242340

Get a can of carb cleaner spray and start the engine from cold and spray small amounts over the vacuum area's such as manifold gaskets/vacuum pipes/fuel injectors etc and if there is a leak you will see and hear the difference straight away. Be careful not to spray this onto an hot exhaust as it is flamable.

OK did that nothing when it starts cold the rpm is 1000 - 1300ish than in about 4min the idle retards down to norm idle than up to 1000s. the change continues till you shut it off. the changes are intermitents in seconds. its a cycle the sounds like something it forcing idle down. This car has 145k, and has not been altered in any way. all factery.

[eric242340]

You will need to read the fault codes next, it may be the air mass meter but the codes will confirm or deny this.

[sthomen]

Ok, I will work on that next week. wont be driven. I did see a crack on the plactic frame that holds the wires in the mass air flow. the wires are still intact.