I just did a bunch of stuff to my car over the last two weeks. Rear end, rear brakes, T-5 swap, and headers. Finally took a ride this evening.

When started the motor idles fine, but after its driven for a few minutes, it dies when I push in the clutch and hit the brakes, I've looked for a vacuum leak and don't find any.

It doesn't sputter or anything, just quits. Like the idle is set too low. Then it's fine again when re-started.

Other than this the motor runs fine.

Any ideas?

 

as posted before check your TPS.

 

Respectfully. Check it for what?

 

Back probe the TPS sensor and confirm the voltage.

Tuned Ports like it anywhere from .48v-.62volts

If it's higher or lower than that, then.. your idle
problem has been located. If the TPS in good shape,
try cleaning your IAC, if it hasnt already, dirty pindles
can cause weird idle issues from time to time.

I had a idle issue, and it turned out to be
a vaccum leak at the brake booster.. So they
can pop up anywhere!

Good luck

 

Whats an IAC?

I was wondering about the brake booster. I had it off when I put the clutch pedals and master cyl in. Guess I could disconnect and plug the vac line and take it for a spin...see what happens.

 

Right below the TPS, is a 4 pronged plastic sensor that
screws into the coolant passage of your throttle body.

That is the IAC (Idle Air Control valve)

I don't recommend buying one.. $60.00!
rarely do they go bad.. but, they get dirty =)

It takes less than 10mins to clean it, and even less
to check yur TPS voltage! Check out the tech articles
on the homepage, it'll teach you everything you need
to know!

As long as your have elementary electrical knowledge!

Disconnect the line from the booster, and vise-grip
the line closed. So your don't have a vac leak..

Don't drive your car like that, dangerous!
But, check to see if it does anything =)

 

Good idea. My wife's Escape had bad IAC valve. It did like mine is doing now, except that the Ford acted up when you started it. Mine works fine when started, but acts up after you've been driving for a few minutes. I think I'll check that first since I flunked elementary electricity.

Can the goobers at Autozone check the tps?

No offense if you're an Autozone goober.
----------
BTW Dangerous is my middle name. Just joking. It's getting late.

 

Haha, no ..Im not a autozone goober!

But, I think thier OBDI scan tool should be able
to pick up the TPS voltage.. Im not positive.
I took my car down to a small time auto
shop when my Voltohmeter was broken.

He checked my TPS for free! Ask around..

But, I suggest you learn how.. It'll come
in handy the future (trust me, lol)

**in response to dangerous, without any vacuum
at the booster, your pedal will be very firm.. It'll
take a tremendous amount of leg power to stop
the car.

So yea.. Dont go "Red-lite-running"

 

Good advice. Thanks for the tips.

 

I've been looking over the instructions for setting the IAC. What's the ALDL? Is that the connection point under the dash on the driver's side?

The car always idles fine when started until you start driving. Even when its hot. It'll stall pulling up to a red light, then idle fine when you crank it back up, only to stall at the next light.

It seems like if my IAC or TPS is screwed up, it would act up all the time.

 

Yea and no.

After the car is warmed up, it's in Closed loop. Using all of
the sensor readings on the engine.. If any of those are out
of calibration.. closed loop operation could aggravate the
problem more so.

I think its a vacuum leak, or intermittent spark energy.

But, we need more information.

Any codes? does it studder or just shut off when it stalls?

It sounds like you say it studders when the engine
is underload or in 'D'.

 

I'm putzing along and everythings running fine. Push in the clutch and the tach goes to zero. Restart it by letting out the clutch and she'll kick right back off and cruise just fine, but die again when you push in the clutch again. Stop the car and restart it with the key and everything's ducky until you start driving again.

Could changing from the auto to the T-5 have upset the computer? There's a four prong connector from the auto that's just tied up under the car for now.

 

The only way it would screw with the computer is your VSS.
(Vehicle Speed Sensor) I doubt it would cause such a problem.

How long ago did you do the T-5 swap? was the car fine, &
then start acting up? or has it been doing this from the start?

Im not familar with the T-5 swaps, maybe try ducking your
head into the Transmission/Drivetrain forum?

 

The problem when I did the T-5 swap, but I also changed the rear gear ratio, added 1le rear disc brakes, and changed from stock exhaust to headers at the same time, not to mention all the thrashing under the dash to add the clutch pedal..

I removed my IAC valve to clean it, and decided to get a new one instead. It was really crudded up bad and the plunger had a groove worn in it.

Now the car idles somewhat. Usually it idles roughly at about 1200 rpm, but sometimes it surges between 500r and 1500r while sitting in neutral. I get a CHECK ENGINE light anytime it's 'idleing' but it goes out after I get going again.

The motor only feels smooth when under power. When cruising at constant rpm, it feels rough, and it idles rough.

As an experiment, I tried setting the cruise control on my way to work this morning. It would not set. Makes me think I have a giant vaccuum leak somewhere. Just don't know where.