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Sick Sable


bowtiebutch's Avatar
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03-30-05, 01:07 PM   #1  
bowtiebutch
Sick Sable

Last month:

I have the 96 Merc Sable 3.0 single overhead cam with 58,000 miles on it. Driving at any speed hot or cold it stutters, it hesitates and backfires occasionally on accelleration and dies at stop lights. I took it to the shop and was told to change egr, new double platinum plugs, wires, and clean the throttle body. All of this plus a new pcv valve and no change. I'm inclined to think it may be the tps sensor.

Today:

After a new TPS, fuel filter, Mass air flow sensor and other parts it still had the same symptoms. I took it to a out of the way shop on a mechanic's farm. He double checked everything. He disconnected the battery for 20 minutes. He said ford products pcm's somtimes take awhile to clear and reset to factory specs while GM products only take a few minutes. Seems ford cars retain residule current in the pcm for some time. I was skepticle but he didn't charge me anything so I followed his advice and drove it for a couple days. The car ran like new and it set a P0430 code which indicates a catalytic converter malfunction. Saturday the pcm cleared itself and the service engine light went out. Today it's back to the same symptoms but with no service engine light. Any suggestions on a fix would be appreciated thanks.

 
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03-30-05, 01:31 PM   #2  
It could be restricted exhaust. Shake the converter and see if it rattles. If so, the ceramic monolith is broken and pieces are lodged sideways, restricting exhaust.

 
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03-30-05, 01:39 PM   #3  
bowtiebutch
Posted By: Kestas It could be restricted exhaust. Shake the converter and see if it rattles. If so, the ceramic monolith is broken and pieces are lodged sideways, restricting exhaust.

Which converter is for bank #2?

 
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03-30-05, 01:53 PM   #4  
Backfire is a timing issue.

One thing that could explain it all, would be, induced voltage by nearby sparkplug wires. This would cause the plugs to fire out of sequence.

Your wires must be fastened to the engine using the OEM snap connectors, and must be laid out as originally designed. No wires may touch another. Parallel wires tend to induce voltage. Regardless, be sure they are strung correctly.

A top grade wire may also be required. Low cost wires should be suspect because they offer less insulation from induced voltage.

Mist some water on them and see if the engine stumbles worse or dies.

I also might suspect a bad o2 sensor, which would contribute to incorrect fuel mixtures. But I would wait until you eliminate any wire issues.

 
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03-30-05, 02:23 PM   #5  
bowtiebutch
I bought the top of the line Bosch wires and strung them like original. None are touching but will try misting later this eve. As far as the O2 sensors two shops confirm they are working fine. The miss isn't continious just whenever it feels like it. The backfire is when you floor it from a dead stop and this dosen't happen every time only occasionally. Oh and the shop resychronized the cam sensor but didn't help. Thanks

 
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03-30-05, 02:41 PM   #6  
In others words,
- it missfires occasionally, at any speed.
- it only back fires sometimes, when you floor it from a dead stop.
- it dies stoplights

Otherwise, the car has full power in all ranges?

Please clarify when it dies. Does it die at all stoplights?

 
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03-30-05, 03:18 PM   #7  
bowtiebutch
Yes the car seems to have full power at all speeds after a hesitation. The hesitation seems to be on acceleration at all speeds. No it only dies once in a while. Like maybe twice a week. My wife drove to work this am and expierenced an occasional miss and it died once. On the way home no problems. The PO0430 code is still in the computer but no light.
The backfire happens at the dead stop it will hesitate then pop in the intake then take off with full power, but not all the time.

 
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03-30-05, 03:48 PM   #8  
Very irractic symtoms. Too many ideas, or rather, not enought, in my head to settle on any one. I'll be gone the rest the week so won't reply soon.

 
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03-31-05, 03:27 AM   #9  
you may have to leave it at a shop so they can drive the vehicle and get it to act up and see what they find.
these cars had alot of cam sensor and syncronizer problems and perhaps the snchronizer is getting worn out and affecting the cam sensor readings to the computer.

 
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