Acceleration malfunction AFTER $600 in repairs

Tiny
ARLEER157
  • MEMBER
  • 1998 FORD TAURUS
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 150,000 MILES
The problem is that the car will no go over a certain amount of Revs. I can never seem to get the revs above 4000 without the engine choking, and this amount constantly decreases as the car gets hotter. The hotter it gets, the less revs, meaning I have to stop and wait a good 20-30 minutes every 30 miles or so.

Multiple repairs have been done, and now the on-board engine checking system has proved useless.

OBD2 Readouts:

Issue 1: Idle Air Control Valve Malfunction (Plunger stuck open)
Solution: IAC Valve replaced completely, did not clear code. (Aftermarket BWD)

Issue 1.1: Mechanic suggested EGR valve may be faulty and causing IAC valve to stay open.
Solution: EGR Valve replaced completely, code cleared. (Aftermarket BWD)

Issue 2: IMRC Valve Stuck Open
Solution: Completely replaced IMRC directly from Ford, code cleared.

Issue 3: O2 Sensor circuit malfunction, Bank 1 Sensor 1; O2 Sensor circuit malfunction, Bank 2 Sensor 1.
Solution: Both sensors replaced with Bosch aftermarket sensors, codes cleared.

Parts Total: Roughly $600

I had figured that after doing all of this, the engine would run okay, but the problem remains. I cannot accelerate effectively, which is making it very dangerous to pull onto roadways and highways, nor can I get anywhere further than 20 or 30 miles away in a short amount of time.

The engine is no longer giving codes, but it still having issues. I prefer to do these things myself, but I'm getting to the point where I may have to bring it to a mechanic, and practically shower him with money.

My current theory, after doing a lot of research on ford repairs forums, is that there is a problem with the Catalytic converters, which is dreadful to me considering how expensive they are.
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Thursday, January 6th, 2011 AT 11:21 PM

6 Replies

Tiny
ARLEER157
  • MEMBER
Any and all assistance is appreciated, I'm quite close to just fixing up my old 1990 Dodge Ram, at least I know that would actually run.
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Thursday, January 6th, 2011 AT 11:24 PM
Tiny
WRENCHTECH
  • EXPERT
You may be on the right track with the Converters. You would have to remove one of the 0/2s and take a pressure reading from the exhaust. Anything more than 1 or 2 PSI would indicate a restriction.
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Thursday, January 6th, 2011 AT 11:36 PM
Tiny
ARLEER157
  • MEMBER
My intention was to just completely remove the converter segment of the exhaust and drive it up and down the backroads to see if it fixes it. Unfortunately, the exhaust is so rusted tight that I've spent weeks spraying with PB and they still will not come off.
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Thursday, January 6th, 2011 AT 11:43 PM
Tiny
WRENCHTECH
  • EXPERT
That's why the pressure test is much easier. You may be able to rent or borrow that gauge from one of the auto parts chain stores.
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Thursday, January 6th, 2011 AT 11:53 PM
Tiny
ARLEER157
  • MEMBER
I know it's been a month, but what can I say, money is tight.

So I took it to a muffler shop, mechanic confirmed a backup of pressure in the upstream portion of the exhaust. Due to the machining of the car's exhaust system, it would not be possible for him to replace one of the converters, so the entire exhaust segment (Banks 1 and 2 from engine to middle heat-sync) was replaced directly from the dealership, total came to around $650

Problem persists. I'm close to selling this to a dealer, and never buying another Ford in my life.
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Tuesday, February 8th, 2011 AT 7:20 PM
Tiny
WRENCHTECH
  • EXPERT
Apparently they were more concerned with selling you a converter than performing an accurate test. They obviously misdiagnosed the problem.
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Tuesday, February 8th, 2011 AT 7:43 PM

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