Help? Is it my Engine or Transmission - Low performance? No power? Transmission slip

[triebold]

Hello everybody, I need your help...

I picked up a 2001 Mercury Sable Wagon with the 3.0L DOHC V6 - Duratec engine and the AX4N transmission. It has 119,000 miles with no rust. I picked the car up cheap because it was running bad and throwing the codes PO133 (02 upstream sensor) and (PO303 (#3 misfire)...I thought easy fix. I got it home and cleaned the Mass air flow sensor, replaced 02 sensor, plugs and wires, fuel filter, air filter and the coil pack (had cracks), re-connected the battery and cleared the codes. I started the car and it purrs like a kitten, no codes or misses but smells a little rich. I backed it down the driveway and down the road I go. Everything is going great until I kick it down to pass, it seems like it has no power, the RPMs go up the trans drops a gear but it seems like it's lacking power or the transmission is slipping like the trans was low on fluid, so I took it to the Ford dealer to have the trans fluid flushed out, the old fluid looked and smelled fine, just a little dirty. I took it home and still the same thing. I'm at a loss, the car runs,drives and shifts great as long as you don't floor it. I don't know what else to do...I NEED HELP. Thanks, Keith

[shorod]

Welcome to the forum!

You mention that the tranny drops a gear and the rpms go up. Do the rpms go up just because the tranny downshifted, or do they continue to climb from the accelerating engine? Maybe the secondary intake runner system is not working properly on the car which should open somewhere around 3800 rpms if I recall correctly. In 2001 I think the IMRC was electric rather than vacuum actuated.

Do you have access to a scan tool with the datastream capability? Did you make sure to get all the intake air tubing properly and securely installed? Is the Engine Coolant Temperature (ECT) sensor within spec?

-Rod

[triebold]

Originally Posted by shorod

Welcome to the forum!

You mention that the tranny drops a gear and the rpms go up. Do the rpms go up just because the tranny downshifted, or do they continue to climb from the accelerating engine? Maybe the secondary intake runner system is not working properly on the car which should open somewhere around 3800 rpms if I recall correctly. In 2001 I think the IMRC was electric rather than vacuum actuated.

Do you have access to a scan tool with the datastream capability? Did you make sure to get all the intake air tubing properly and securely installed? Is the Engine Coolant Temperature (ECT) sensor within spec?

-Rod

Thanks Rod,
What I mean is when I floor the gas pedal to pass it works like it should but has no power.

I did replace both upper and lower intake gaskets and checked for cracks plus I checked all vaccum lines, everything looks perfect! The engine idels and runs like it should.

I checked my mileage this morning and only got 15.5 MPG last tank full. I'm woundering if my cats are plugged? The guy I bought the car from said the check engine light had been on for a long time. If the car had no spark on #3 but fuel was still going into the cylinder and out the exhaust could that plug a cat?

It's funny, when I drive the car easy it runs and shifts normal, but when I get on the gas it's just a dog.

[shorod]

It appears that 24V V6 in the 2001 Taurus does not have a secondary intake runner system like the smaller Duratechs did, so that shoots that theory. Does the engine seem to consistently have power under a certain engine speed, or does it lose power any time you go full throttle, including from a dead stop? A catalytic converter that is trying to convert raw fuel to water will get extremely hot and eventually self destruct.

Since the code is showing up for HO2S number 1 that would not necessarily point to a converter issue though. You may want to verify the suggestions below from the factory service manual:Contaminated HO2S sensor.

• Exhaust leaks.
• Shorted /open wiring.
• Improper fueling.
• MAF sensor.
• Deteriorating HO2S sensor.
• Inlet air leaks.

-Rod

[trannyman52]

sure sounds like cat converter could be plugged

[triebold]

It was the back cat, replaced it and now I have tons of power. Thanks everybody!!!