: newbie question, hit full throttle and it goes fas then slows down then fast


Chief yelling alot
07-03-2002, 12:11 PM
not for me but for my bro he has a 86 3/4 ton GM van with 350/th400

with new carb (bout 1 year old) new pump and filter (the glass one with the replaceable element)

so we went crusing up north and whene he got on a hill to pas someone and you hit full throttle the engine speeds up then slows down then speeds up then slows down, like someones is keep stomping on the gas then letting go the hitting it agen.

this is verry anoying any ideas

he has a Q-jet

I dont know where to look, first time I have com across this problem.


thanks

FordPowr
07-03-2002, 12:16 PM
prob not getting enough fuel....try fuel filter

Chief yelling alot
07-03-2002, 12:20 PM
Originally posted by FordPowr
prob not getting enough fuel....try fuel filter

its fine :confused:

1SAWB
07-03-2002, 12:22 PM
CHECK THE FLOAT HEIGHT IT IS MOST LIKLY SUCKING THE FLOAT BOWL DRY

Chief yelling alot
07-03-2002, 12:29 PM
Originally posted by 1SAWB
CHECK THE FLOAT HEIGHT IT IS MOST LIKLY SUCKING THE FLOAT BOWL DRY

yeah I kinda thought that but I asumed that the carb came pre set, but a long time ago not to long after the new carb he did get a mechanic to tune it :confused:

snacksnack
07-03-2002, 01:12 PM
rev limiter:flipoff2:

IndyCJ
07-03-2002, 01:23 PM
Fuel pump.

I had the same thing happen several years ago, rebuilt the carb, new fuel filter, better gas, new carb, etc, etc, etc.

Turned out to be the fuel pump......

Chief yelling alot
07-03-2002, 01:26 PM
fule pump about 4 month old

MattS
07-03-2002, 01:27 PM
I agree.

Originally posted by 1SAWB
CHECK THE FLOAT HEIGHT IT IS MOST LIKLY SUCKING THE FLOAT BOWL DRY

snacksnack
07-03-2002, 01:32 PM
ive actually had the same problem as well and it was the fuel pump

LAME
07-03-2002, 01:37 PM
Originally posted by Chief Yelling Alot
fule pump about 4 month old

Just because it is new, doesn't make it work correct. Check it out.

offroadr35
07-03-2002, 02:12 PM
Originally posted by LAME


Just because it is new, doesn't make it work correct. Check it out.

amen to that

Magoo
07-03-2002, 02:20 PM
Muffler bearings! Try them....


JK, Fuel pump was my first suspect, make that 4 for the fuel pump.

HeyBeerMan
07-03-2002, 02:41 PM
I have the same problem.

Its called wheelspin!! :flipoff2: :flipoff2:

twistedmetal
07-03-2002, 08:57 PM
Did you check to make sure that he's not actually pushing down then letting up on the go-pedal?:flipoff2:

Sounds like fuel pump. JMO.

cruisercrazy
07-03-2002, 10:18 PM
It also could be the screen sock in the fuel tank.They will get pluged.It's usually worse when the tank is below 1/2 tank.

440-fide Ramcharger
07-05-2002, 10:04 AM
I finally pulled the tank on my Ramcharger due to a low power problem at WOT. I found a plugged fuel sock and the 5/16 line was down to about a toothpick size hole. Fuel pressure guage was going down to 3-4 psi before, and stayed 6-7 after. This is merging onto the hiway and punching on. Idle fuel pressures do not tell you much. Bottom line, put a fuel pressure guage on it with a length of hose so you can put it under the back of the hood and see it while driving. If it is a restricted pick up, it may get better after blowing air back through the line to the tank. Also, you said the new filter is clean and new. Are you SURE there is not another plugged STOCK one hidden anywhere in the line? Good Luck, :usa: :usa: :usa:

JeepinIan
07-05-2002, 10:13 AM
Does the accelerator pump work? It sounds like it is starving for fuel during the transition betwen part throttle & full throttle.