Studdering under load
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Joined: May 2009
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Studdering under load
I have a 1996 F-250 with a 300 I6, on acceleration the engine studders and cutts out but does not die. On surface streets it is driveable but on the expressway it stumbles so bad that I cant get to Highway speeds. If I let up on the accelerator the studdering stops but then I cant accelerate. From a dead stop I mash the pedal and after a few hiccups it accelerates but once it is under continueous load (like driving on the interstate) it looses almost all power but will still idle smooth and rev in park without hesitation.
In efforts to fix this I have replaced
Plugs
Wires
Distributor Cap
Rotor Button
Fuel Filter
One O2 sensor (Connector is melted on other one have not got replacement yet)
Throttle Position Sensor
Cleaned Mass Air Flow Sensor
I have not yet checked fuel pressure
AutoZone says it is throwing a code for insuficent EGR flow
Could the EGR cause this?
Any help would be appreciated. This is my work truck and I need it on the road asap. I am a contractor so no truck, no siding trailer, no money
In efforts to fix this I have replaced
Plugs
Wires
Distributor Cap
Rotor Button
Fuel Filter
One O2 sensor (Connector is melted on other one have not got replacement yet)
Throttle Position Sensor
Cleaned Mass Air Flow Sensor
I have not yet checked fuel pressure
AutoZone says it is throwing a code for insuficent EGR flow
Could the EGR cause this?
Any help would be appreciated. This is my work truck and I need it on the road asap. I am a contractor so no truck, no siding trailer, no money
Elder User
Joined: May 2007
Posts: 548
Likes: 0
From: Sparks, NV
you could have detonation from your EGR not working. since your engine is calibrated to run with EGR to take up space in the cylinder, you have too much of a fuel/air mixture for your timing to light off at its current setting. i know my 302 had too much timing and it was doing exactly the same as your is now. i backed the advance of a bit and the stutter went away.
too much air/fuel and lots of timing will try to stop the piston because as explosions expand, they like to force anything out of their way. get the egr back to working order and it SHOULD go away. or remove the "spout" and adjust the timing back a couple degrees.
in short, the explosion of the bigger fuel mixture is stopping the piston from traveling up, which stops the motor and will eventually stop the engine for good via cracking something and ot breaks causing massive damage.
too much air/fuel and lots of timing will try to stop the piston because as explosions expand, they like to force anything out of their way. get the egr back to working order and it SHOULD go away. or remove the "spout" and adjust the timing back a couple degrees.
in short, the explosion of the bigger fuel mixture is stopping the piston from traveling up, which stops the motor and will eventually stop the engine for good via cracking something and ot breaks causing massive damage.
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