Engine jerks at highway speeds
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Engine jerks at highway speeds
This seems to be a weird problem, after I have been out on the highway for about 2 hours steady the engine will start to run really rough like it is going to die, if I take it out of overdrive or accelerate it will smooth out when you pick up rpm's. If I come to a stop sign when i accelerate it will hesitate until the throttle is pressed about half way then take right off and run good. I had it at the dealer and they replaced the plugs, wires, maf, and the problem still exist. Could this be a fuel pressure regulator problem. Its a 94 with 115,000 on it 4.0L Service engine light will come on and off I had it checked and they said it was the 02 swnsor but i have never seen one do this.
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Hi there, I have a 96 Explorer that used to "surge" on the highway, I could almost time it to every 15 seconds, it would also almost die at stops--but not always and I could accelerate past these problems--turned out all 3 02 sensors were bad, replaced those and problems were gone. However I replaced my plugs and wires yesterday, and today had a serious misfiring going on but only at highway speeds or complete stops--but in park everything sounded right--turned out I had too long of boots on one spark plug wire and it had laid on the headers and melted right through--I put on one of my old plug wires and the misfiring is gone. Not sure if these ideas help but that's what mine did--by the way after replacing my 02's my gas mileage improved.
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From: 3rd Rock
Originally Posted by heavyd86
This seems to be a weird problem, after I have been out on the highway for about 2 hours steady the engine will start to run really rough like it is going to die, if I take it out of overdrive or accelerate it will smooth out when you pick up rpm's. If I come to a stop sign when i accelerate it will hesitate until the throttle is pressed about half way then take right off and run good. I had it at the dealer and they replaced the plugs, wires, maf, and the problem still exist. Could this be a fuel pressure regulator problem. Its a 94 with 115,000 on it 4.0L Service engine light will come on and off I had it checked and they said it was the 02 swnsor but i have never seen one do this.
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From: Phoenix
For an old car like a 1994, you need to make sure all the basics are OK - plugs, wires, PCV valve, air and fuel filters, O2's for sure. Not related to your issue but good maintenance is to clean the MAF sensor and IAC valve. The fuel pressure regulator is an integral piece of the puzzle - but usually if it is bad it is bad all the time - not just after 2 hours on the highway.
You seem to have an unusually issue. I am thinking the catalytic converter might be going out. Well they don't start to go out - they just fail. The honeycomb structure inside can break up and go sideways. Exhaust then casn't get out and the engine acts up. Sometimes it just dies but most of the time it fights to keep going and bucks a bit.
Then the loose stuff realigns and the motor runs as normal.
But if you are getting O2 sensor codes, fix that first and then go from there.
You seem to have an unusually issue. I am thinking the catalytic converter might be going out. Well they don't start to go out - they just fail. The honeycomb structure inside can break up and go sideways. Exhaust then casn't get out and the engine acts up. Sometimes it just dies but most of the time it fights to keep going and bucks a bit.
Then the loose stuff realigns and the motor runs as normal.
But if you are getting O2 sensor codes, fix that first and then go from there.
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I had the cat converters checked and they are fine. I also forgot to mention that after the engine cools overnite it will run fine the next day and the problem does not show up again until you are on the highway for about 2 hours. The service engine light never comes back on until then. But I will change the 02 sensors. Thanks for the input
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