Strange pulse

[Peter Vincent]

My truck is acting a little strange. When I start it up and put it in reverse the engine "pulses" for about 10 seconds then it stops. It only does this right after I start it, never any other time. Pulse is the best way to describe it. The tac doesnt really move with it. The only mod I have done is a Dynaflow cat back. Any ideas what it could be?

Thanks,

Peter

 

[Todd Z]

Does it act like your stepping on and off the gas????

Do you have the AC on or the switch in any other position than off???



I think the Iac motor needs a cleaning...

Todd Z

 

[Peter Vincent]

It is similar to stepping on the gas pedal but very fast, almost like you are just tapping the pedal. The ac is always off.

 

[Kevin Long]

My ST started doing that at about 30k miles, I took it to the dealer 3 times and they told me there was nothing wrong with it. I took it to 2 different dealers and got the same response from both.

It just seems something I have to live with. When I start it, I give it a little gas for a few seconds and that prevents it from acting up.

 

[Todd Z]

Does it do it when the truck is facing down on a hill??? You could be loosing fuel due to the the way the pump is located in the tank....



I say clean the IAC and go from there..

Todd Z