Hissing dropping pressure when cold

[JLDickmon]

My '00 Lariat has never done this nor my '99 XL dually however my '99 XLT SRW 4wd just started doing this. I have warmed the truck up for 20+ min. and it still does it for quite some time after starting to drive it. Throttle is non responsive at times and when the truck does this it drinks the fuel. Normally this subsides about 15 min. into the drive, however I would like to resolve this ASAP.

Thx Jimmy

nothing to resolve.. it's normal.

some guys have been know to gut the valve, however.

 

[jeeps and fords]

Does anyone run one of the radiator covers across the front? I've noticed with the after market exhaust my truck sometimes will never keep up to temp even with hard driving.

 

[iracemine]

yup, I rock the cardboard all winter every winter.