Rpm Surge on startup

[jman_07]

Ive noticed even with a warm engine right when the engine starts there is a surge in the rpms which drops right away but it happens everytime its like someone is stepping on the gas when you start the truck what could cause this MAF sensor????


2001 Explorer XLT 4.0SOHC

 

[jman_07]

anybody?

 

[steventadams]

As with most rough idles the first step is to take a look at and clean the MAF and IAC. If that doesn't work check around for some vacuum leaks or a vacuum tube disconnected.

 

[briwayjones]

Even when the engine is warm a second or two RPM surge to about 1200RPM is normal.

 

[Blacksheep Josh]

yeah, when i start mine, it goes up to about 1200-1500 dependin gon how cold or what incline i'm sitting on... could it be the rest of the "starting power" from the starter letting off? maybe it's just turning the engine a little bit more..

i have no idea if what i said makes sense. lol.

 

[Puckboy106]

RPM Surge

My 98 just started this. It starts and immediately goes to 2100 rpm and settles to 900 rpm with 15 seconds. It seems coincident with replacing the Battery. I dont think the computer is fried....runs just fine after that....I'll check the MAF and IAC sensors and look for Vac leaks....any other hints?