Engine Performance problem
1998 Ford Taurus 6 cyl Front Wheel Drive Automatic 65000 miles
I just got this car. When I first start teh engin it used to idle high and would not go below about 1200 rpm. I cleaned the MSA and it now drops to the 800 range.
When I am driving, it feels like you can get to the speed you want and you can take your foot off the gas and it will stay at that speed until you brake. It is very slow to slow down on its own. When I am going down a small hill it will pick up speed even if I shift down to drive from overdrive.
I read something about the fuel pressure regulator possibly leaking more fuel than it should. Just want to confirm before I replace it.
So what I get is that the RPM is high and will not slow down on its own
do you have check engine light on and if so have to check for codes 1st
I would suspect idle air control valve and also check for vacuum leaks
let me know
The RPM does come down, it just kind of hangs there for a long time before it starts to come down. When I stop, the idle drops of to 800.
An example is when I speed up to say 50kmh to go down a flat street, I can let the gas off and it stay at that speed for at least a few blocks before starting to slow down. I haven't waited long enough to see if it will come right to a stop on its own. That will be another trial tomorrow.
The RPM drops to about 800 when the vehicle is stopped. When I start the car with my foot off of the gas pedal, it will rev up to about 2500 rpm. Then it will drop, but takes about 30 seconds to get to 800 rpm. When I shut it off and start it up again, it will sit around 1500 rpm and then slowly come down to 800 rpm, this takes about 30 seconds.
If I rev it up while in park, it will drop fairly quickly to less than 2000 rpm, but will take about 30 seconds to get back to 800.
I did look for vacuum leaks and couldn't find any. I will look again tomorrow. Are there any certain hoses that I should check real well?
The check engine light isn't on.
May, 7, 2009 AT 9:01 PM
Lets try and clean idle air control valve
check PCV valve vacuum hose
let me know
May, 8, 2009 AT 11:25 AM
I pulled the IAC valve. There was some black build up, so I flushed it out. One thing I noted was that the plunger was not seated even when I turned the key on. With the key on, I unplugged it and nothing happened. I then left it off and covered up the holes on the manifold. I then started the motor. The idle was about 500 rpm. When I reved it up the rpm quickly came back down.
I looked at the PCV hose and it looks good. I pulled the PCV out while it was running and put my finger over the end of the valve. There was a strong vacuum and I didn't hear any leaks.
May, 12, 2009 AT 10:40 PM
The car is for my daughter and she came to pick it up last weekend, so I went ahead and replaced the IAC valve. It may have helped a bit on the engine braking when it is put into D from OD.
The one thing that was noticable is that when I pulled up to a stop sign or light, the rpm dropped to the 600 rpm range. I thought this was better.
Not sure if it was the fix, but it appears to have help some.