1998 Ford Taurus Idle Rough, Need Help

jthomas194 · 02-24-2009, 09:55 PM

Hi,
My 1998 24v 3.0l dohc taurus is experiencing a rough idle. I recently switched out my DPFE sensor since I was getting a p0401 code, and had heard that this sensor was normally the culprit. Well, I had to take the throttle body off to get to it, and the replacement gasket was not the right size, so I used the old one again when i put the throttle back on. Also, I made a rookie mistake and used some carb cleaner on my throttle body before I read in my manual that the throttle has a special coating and cleaning it is not recommended as it will destroy this coating which is supposed to create a good seal. Anyways, my question is, assuming their are no other vacuum leaks, could my rough idle be due to the the old gasket not sealing correctly, or did I just destroy the coating on the throttle that helps seal. I hope that a new gasket + some gasket sealer of some sort would correct this problem. Any thoughts or advice would be greatly appreciated. Also, what would a new throttle body cost. I hope I didn't mess mine up completely by using carb cleaner on it.

theoldwizard · 02-25-2009, 03:27 AM

Quote:

Originally Posted by jthomas194

Hi,
My 1998 24v 3.0l dohc taurus is experiencing a rough idle. I recently switched out my DPFE sensor since I was getting a p0401 code, and had heard that this sensor was normally the culprit.

Not always true ! It depends on the engine. Another common cause of P0401 is a clogged passage from the EGR valve to intake manifold, usually where it comes into the manifold.

Quote:

Well, I had to take the throttle body off to get to it, and the replacement gasket was not the right size, so I used the old one again when i put the throttle back on. Also, I made a rookie mistake and used some carb cleaner on my throttle body before I read in my manual that the throttle has a special coating and cleaning it is not recommended as it will destroy this coating which is supposed to create a good seal.

I don't think it will hurt anything. That coating was placed there so that no air would get past the throttle plate at closed throttle. During cool, damp weather, ice would lock the plate in the bore.

Quote:

Anyways, my question is, assuming their are no other vacuum leaks, could my rough idle be due to the the old gasket not sealing correctly, or did I just destroy the coating on the throttle that helps seal. I hope that a new gasket + some gasket sealer of some sort would correct this problem. Any thoughts or advice would be greatly appreciated. Also, what would a new throttle body cost. I hope I didn't mess mine up completely by using carb cleaner on it.

Replace the gasket and don't worry about the coating. A new throttle body from Ford would be over $100.

If that doesn't do it start looking for over vacuum leaks.

jthomas194 · 02-25-2009, 06:49 AM

Thanks so much for the reply. I will go ahead and replace the gasket. However, I found out that the idle roughness seems to get worse when I turn the heat on full blast. Why would this be? Thanks again.

theoldwizard · 02-25-2009, 07:46 AM

Quote:

Originally Posted by jthomas194

Thanks so much for the reply. I will go ahead and replace the gasket. However, I found out that the idle roughness seems to get worse when I turn the heat on full blast. Why would this be?

Alternator is working harder to supply power to blower causing a bigger load on the engine.

jthomas194 · 02-25-2009, 08:08 AM

Thanks again Wizard. Very much appreciated.