I have a 98 f150 4.6l vin w, recently i encountered a problem with my truck, when i start it up and give the accelator a quick shot of gas i can hear the air get sucked in, but the rpms dont increase until a second later, there's a delay. If I hold the pedal down during this delay the truck almost stalls, let go of the pedal and it idles ok, But if I slowly press the accelerator it reacts fine, its also ok once my truck warms up. Already removed throttle body, found clogged egr ports, cleaned them and replaced the idle air control valve. Replaced all the gaskets for throttle body, iac, and egr. Same thing.

Any ideas?

 

Surely someone has a suggestion that might help.

 

Is there a moderator here that can help me? 81 views and no suggestions. Need to get this fixed.

 

that answers it to me. Not completely sure, but I feel like that's just cold engine behavior?? It's not warmed up and you're not getting enough gas. So if you're heavy on the throttle when it's completely cold, it's not gonna rev smoothly

Here's an idea, sounds similar
https://www.f150forum.com/f6/2003-f-...oblems-149926/

 

If its not idling rough or throwing a dtc then I think it may just be cold engine behavior. The only thing that I could think to check would be a vacuum leak off of the throttle body. But normally that would cause a choppy idle. it really is a tricky one. Good luck with it though!

 

I might be inclined to agree with the cold idle theory but it never did this before, this is something new, i probably should have mentioned that my truck was put away for the winter, just getting it ready for the season. I have heard that these trucks are notorious for having a throttle delay, but this is something beyond that i think. I added stabilizer to the tank before putting it away, so i don't think its bad gas. I'm gonna test the tps and have a look at the fuel pressure regulator, I will definitely post when I figure it out. Thanks for the replies.