Done everything still running terrible.

[Bj6788]

Recently on my 2001 sport trac 4.0 sohc, I did head gaskets, timing chains and guides front and rear, had heads magnafluxed and surfaced, all new gaskets, new plugs, wires, etc. Since I've got it finished it just doesn't run right. Super sluggish unless barely giving it any gas. If gas is very lightly applied it runs good. If you punch it, it shifts into passing gear but hardly accelerates it all and seems to take forever for the RPMs to climb. After it warms up it sometimes spits back through the intake. I've tried everything, changed every sensor, I'm just scratching my head I don't know what to do. Any help would be greatly appreciated. Thank you

 

[Bj6788]

Recently did head gaskets, timing chains and guides front and rear, had heads magnafluxed and surfaced, all new gaskets, new plugs, wires, etc. Since I've got it finished it just doesn't run right. Super sluggish unless barely giving it any gas. If gas is very lightly applied it runs good. If you punch it, it shifts into passing gear but hardly accelerates it all and seems to take forever for the RPMs to climb. After it warms up it sometimes spits back through the intake. I've tried everything, changed every sensor, I'm just scratching my head I don't know what to do. Any help would be greatly appreciated. Thank you

 

[EB4X]

Check your throttle position sensor connection/ wiring.....just read a thread exact same issue....new everything put back together and exact symptoms as yours in every way.... this or something else got inadvertently messed up during overhaul process...

 

[XploderPhil]

Really hard to say without more info. First thing come to mind,
Timing

 

[EB4X]

I was initially going to say timing.... especially when he posted this > "it sometimes spits back through the intake"
Possibly off one tooth.

 

[Bj6788]

Check your throttle position sensor connection/ wiring.....just read a thread exact same issue....new everything put back together and exact symptoms as yours in every way.... this or something got inadvertently messed up during overhaul process...

I have swapped the tps sensor with no improvement. If the truck is running and unplug the tps should there be a noticeable change?

 

[Bj6788]

I was initially going to say timing.... especially when he posted this > "it sometimes spits back through the intake"
Possibly off one tooth.

Was my first thought also. But I pulled the valve covers and rechecked.

 

[C420sailor]

What’s the live data telling you? That’ll show a bad TPS clear as day.

No codes?