Fluctuating Idle in PARK

Topic: Fluctuating Idle in PARK (Read 1662 times) previous topic - next topic

Fluctuating Idle in PARK

August 06, 2007, 01:17:21 PM

Hi,

87 Tbird sport 5.0 EFI

In park idle surge some times to 2K rpm sporadic.

sometimes surges when coming to a stop & during stop.

HELP!!!!

Tony P.

Fluctuating Idle in PARK

Reply #1 – August 06, 2007, 01:30:10 PM

Have you scanned it for codes?

My first ideas would be the TPS (throttle position sensor) or the IAC (idle air control) valve.

Fluctuating Idle in PARK

Reply #2 – August 06, 2007, 01:32:23 PM

First thing you need to check, Tony, is the car's computer. It will let you know of any faulty sensors...otherwise you're just guessing at which one is bad.

There are just a few sensors that control idle:
- TPS (throttle position sensor)
- EGR
- Idle bypass valve (aka IAC)
- MAP sensor

From what you're describing it could be a bad TPS. However, you can't discount a clogged EGR or idle bypass valve, maybe even a bad gasket for those, or a vacuum leak somewhere. Again, it's guesswork until you get the codes scanned.

(Zach: Jinx--you owe me a beer

)

Fluctuating Idle in PARK

Reply #3 – August 06, 2007, 07:43:41 PM

intake leak?

Fluctuating Idle in PARK

Reply #4 – August 06, 2007, 10:37:29 PM

If it's the TPS or the IAC,I have them both in great shape.$15.00 shipped for both.I'll bet the TPS as well.

Fluctuating Idle in PARK

Reply #5 – August 06, 2007, 11:01:01 PM

ill call small vac leak or clogged egr which will effect the evp sensor atop the egr,,, which cant report to the map,,,,,,,,,
which hoses a lot of inputs to the eec causing a confussed computer to have trouble controling fuel.

nonetheless, id replace the tps if it aint ever been replaced in your memory. Heck, everyone should.

you can find a fitting capped off where you can put your vac guage on it and see what vac pres you have at idle.

Fluctuating Idle in PARK

Reply #6 – August 07, 2007, 07:10:48 AM

Buy/borrow/rent/ a voltmeter and something to scan codes with and check for codes AND also check to see what your TPS voltage is at idle and if it sweeps properly. That is, make sure it has no dead spots. Check all vacuum lines and connections as well.

Fluctuating Idle in PARK

Reply #7 – August 08, 2007, 08:25:56 AM

Hi all,

Thanks for the Input. Scanned last night KOEO memory code 34, KOER kicked up a 33.

noticed a repaired/pinched vac line to the EGR will repair scan again.

if necessary will replace EGR.

Any body know if newer vehicles used the same EGR?

Thanks again.

Tony P.

Fluctuating Idle in PARK

Reply #8 – August 08, 2007, 12:22:38 PM

Basically, any EGR from any EFI Ford 5.0 with EEC-IV will work. Unsure on the later Explorer models.

Fluctuating Idle in PARK

Reply #9 – August 09, 2007, 10:34:35 AM

Hi,

Repaired Vac line, rescanned got a memory code of 34 and a new KOEO code of 23.

Idle is rock solid in park at 600 rpm.

comments?????

Fluctuating Idle in PARK

Reply #10 – August 09, 2007, 04:06:09 PM

To reset the memory codes, unplug the jumper while the memory codes are displaying. Or disconnect a battery cable.
Code 23= TPS out of specs.

Fluctuating Idle in PARK

Reply #11 – August 14, 2007, 12:29:16 PM

Hi All,

So, ok should i replace the TPS?

By the way how do i tell if my *& came with a 1 row or 2 row radiator, does it matter?

thanx

Tony P.

Fluctuating Idle in PARK

Reply #12 – August 15, 2007, 08:26:56 AM

Bueller?..... Bueller?.....Bueller?...........