engine stumbles at 55 mph

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Jun 9, 2005 | 03:20 AM

#16

kermit

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Laughing Gas

Joined: Jan 2004

Posts: 913

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From: Pensacola, FL

UPDATE:

been working kinda hard this week getting ready to go to the boat, so i havent had alot of time to work on the ole truck. I found out something though.

if i leave the truck in L1 and get on it, it works fine, all the way up to about 4200 rpm,
then if i put it in L2, it almost instantly starts the stumble thing, and if i put it back in L1 i can rev it all the way back up, so i am wondering if this is not a motor problem, but a trans problem somewhere.....

thanks for the help guys, keep her coming...

jamie

Jun 9, 2005 | 04:11 AM

#17

Torque1st

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That can still be a motor problem. The timing chain may have slipped also which can cause power problems. You need to start eliminating possibilities.

Jun 9, 2005 | 04:16 AM

#18

kermit

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Laughing Gas

Joined: Jan 2004

Posts: 913

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From: Pensacola, FL

brand new timing set in it, and all new ignition components...coil, cap, rotor, condensor, points, plugs and wires, and all new rubber fuel lines....the only thing i havent looked at is if one of the steel fuel lines might have a kink in it, with a small hole, but from what i have seen when replacing the rubber lines, there are no problems with the fuel lines.....

also, i went through and already changed out the vacuum lines. kinda wondering if maybe the vacuum modulator on the trans might be shot and is doing something funky when too much vacuum is applied to it?

maybe i will be able to get to the shop this weekend and run the fuel pressure test at speed and see what is up and maybe try a couple of other things.

Last edited by kermit; Jun 9, 2005 at 04:29 AM.

Jun 9, 2005 | 05:57 AM

#19

Torque1st

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Pull the vacuum line to the tranny modulator and see if there is oil in it. If there is the diaphragm may be ruptured which can cause various transmission problems.

Jun 18, 2005 | 01:53 AM

#20

kermit

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Laughing Gas

Joined: Jan 2004

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From: Pensacola, FL

well, just to be safe, replaced the vacuum modulator and checked the float levels in the carb, all is well, still doing it......this is getting anoying(sp), i hate not being able to take my truck on the freeway.

Jun 28, 2005 | 09:41 PM

#21

kermit

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Laughing Gas

Joined: Jan 2004

Posts: 913

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From: Pensacola, FL

new question: it only does it if it is in a gear other than 1st. i ran it in L1 for about 2 miles well above 3000 rpm and no problems, as soon as it shifts into 2 it starts the stumble thing and the same thing for 3, still about 2800 rpm.

help please

Sep 27, 2005 | 10:08 PM

#22

kermit

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Laughing Gas

Joined: Jan 2004

Posts: 913

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From: Pensacola, FL

UPDATE: put new fuel pump in her today, and she is hauling anything you put in it at any speed i want. i missed having her run 80 down the freeway and being able to keep up with traffic.

thanks for all the help guys,

jamie