Stubmle-Surge
Thread Starter
|
Posting Guru
Joined: Jan 2004
Posts: 1,232
Likes: 0
Stubmle-Surge
I have a 95 F150 with the 300 6cyl, and the good old M5OD with 3.55:1 rear end. It is a 2 wd and while running down the road today it started to stumble or surge at around 40 mph, and as long as I stayed at that speed it would continue, however if I gat it some gas this would stop and if I let off it would stop. What's up? It has been a great runner with no problems, its due for an oil change, but the plugs/wires/cap/rotor are all new and checked out.
Elder User
Joined: Apr 2001
Posts: 772
Likes: 0
From: Glen Burnie Maryland
Off idle stumble/surge without same symptoms at idle and under acceleration is indicative of an EGR that's cycling more than it should.
Disconnect the EGR valve, plug the vacuum line and drive it under normal conditions. If the stumble/surge goes away, then pull of the EGR, clean it, and re-assemble it to the engine with a block-off plate (tin can cut out to shape of gasket with a 1/8" hole in middle.). This will restrict the EGR and stop the excess flow causing the stumble/surge.
JWTAYLOR
Replacing the Fuel filter is a good idea but isn't a cause of the problem here. Read the symptoms again.
Larry
Disconnect the EGR valve, plug the vacuum line and drive it under normal conditions. If the stumble/surge goes away, then pull of the EGR, clean it, and re-assemble it to the engine with a block-off plate (tin can cut out to shape of gasket with a 1/8" hole in middle.). This will restrict the EGR and stop the excess flow causing the stumble/surge.
JWTAYLOR
Replacing the Fuel filter is a good idea but isn't a cause of the problem here. Read the symptoms again.
Larry
Mountain Pass
Joined: Jul 2004
Posts: 245
Likes: 41
before trying the above methods i would replace both the throttle body gasket and the upper intake manifild gasket as the stokers tend to collaps and allow un mettered air by. i have the same problem. have not changed the upper intake manifold gasket yet but did the throttle body and noticed a slight improvement. i belive both need to be done though.
Postmaster
Joined: Jun 2001
Posts: 4,496
Likes: 0
I still wouldn't rule the filter out, while not likely its possible....I don't consider 40 mph to be off idle but then I am guessing as to what it could be.
Go to autozone have them pull the codes then post them up, that will get you in the ballpark of the problem and you can go from there.
I wasn't aware collapesd gaskets was a problem on the 4.9, deteriorated maybe but collapsed...interesting...the upper to lower gasket is pretty wide and thick, it would take some age and serious vacuum to collapse that sucker...I'd think.
Go to autozone have them pull the codes then post them up, that will get you in the ballpark of the problem and you can go from there.
I wasn't aware collapesd gaskets was a problem on the 4.9, deteriorated maybe but collapsed...interesting...the upper to lower gasket is pretty wide and thick, it would take some age and serious vacuum to collapse that sucker...I'd think.
Thread
Thread Starter
Forum
Replies
Last Post
NewGuy_99
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
4
May 25, 2006 11:11 PM
