help needed...truck has me worried!!

[TheBigEdbosky]

i just got the truck back together and am slowly putting some break in miles on the new motor. but in doing so the truck is developing some strange driving characteristics.
the major concern that i have is how the truck just flattens out on the decel. bringing the truck up to speed is no problem but once i'm up around 60mph and i let off the gas the a/f meter reads dashes and the truck feels like you cut the ignition until i tap the gas. then it comes alive again and the a/f meter jumps back up.
it doesn't do this at low mph or around town only on the highway or if you stab the pedal and let off real quick.
driving moderately the a/f gauge reads high 14's low 15's. on a more aggressive acceleration the reading will dip to 10.2-mid to low 11.
i'm gonna stay off the highway until i get this sorted out i don't wanna damage anything.
the other thing i noticed is that once i come to a stop after driving the rpm's stay high for what seems longer than usual before they drop to idle. also if i drive up to something then have to reverse the rpm's dip hard then recover.
when i got the beast going i did have to make some heavy adjustment to the throttle body idle adjustment screw and tps.

any help or thoughts on this would be greatly appreciated.
thanks
ed

oh and one more thing. what would cause my upper radiator hose to collapse like there was suction in the cooling system? i noticed this when i popped the hood after washing it.

 

[TheBigEdbosky]

anyone... anybody got any thoughts on this. is it in the tune, because i have a new tune, fuel psi??
any help would be great.

 

[sb306]

I would think tune related. I just put walbro pumps in the lightning. Now tip-in throttle goes lean and takes a second to catch up. On the freeway just tappin the gas, the af will go up to 18:1 then go back to stoich. Mine is running lean until it sees boost. If I see 1 or 2 lbs of boost, then it shifts and goes out of boost it goes lean until it levels out. But, hard to moderate driving is fine, as long as the second pump is on. All of that should be fixable in the tune i would think.

Edit: did i just hijack a thread?? lol

 

[Scarpino]

Just had mine tuned. I called and asked my tuner the same thing.

When I'm crusing and let off the gas...it goes so lean I cant even read it and it feels like its comperssion thats slowing it down until I push on the pedal again. He said that's how its suppose to be and theres nothing to worry about.

 

[INFAMOU$]

Just had mine tuned. I called and asked my tuner the same thing.

When I'm crusing and let off the gas...it goes so lean I cant even read it and it feels like its comperssion thats slowing it down until I push on the pedal again. He said that's how its suppose to be and theres nothing to worry about.

Mine does the same thing as well

 

[TheBigEdbosky]

Just had mine tuned. I called and asked my tuner the same thing.

When I'm crusing and let off the gas...it goes so lean I cant even read it and it feels like its comperssion thats slowing it down until I push on the pedal again. He said that's how its suppose to be and theres nothing to worry about.

if you don't mind me asking, who did your tune? i have been hearing the same thing from a couple of other guys who use the same tuner as myself.

 

[sb306]

Just had mine tuned. I called and asked my tuner the same thing.

When I'm crusing and let off the gas...it goes so lean I cant even read it and it feels like its comperssion thats slowing it down until I push on the pedal again. He said that's how its suppose to be and theres nothing to worry about.

Thats totally normal. You should ride in a high compression car. I was driving my fairmont and shifted into first going to fast. I was only going about 20. It was a automatic with a ratchet shifter. Anyways, the second I did that the tires started chirping and skidding slightly because tehy slowed down so much. The rpms only went up a few hundred rpms. Its "engine braking" it helps you use your brakes less too. :beer:

 

[IneritaSVT]

Normal in the tune especially if you have no cats. Most tuners turn the injectors off on declaration.

 

[yadisisp6]

That's normal.

 

[TheBigEdbosky]

hmm, ok cool. just never experienced anything like that. or that noticeable. i have had hard decels before like when you gun it in 1st and let off. but to hear the motor go quiet like that is just strange. also like i said before i can't understand why my tuner acted like he never heard of such a thing. i think that is what bothers me most now.
thanks guys