Revving high in park?

Hi all,

Car's been acting a little odd last couple times I drove it. This has never
happened before and currently its stupidly cold outside and prolly the
coldest this car has ever encountered (about -30 celcius, -40 with wind) so
I hope its just due to that. Anyway, after around a 1 to 1.5 hour drive last
night and this morning, the car ran fine while driving but when I go to park
the car, as soon as I put the car in Park the engine rev's up to about 2500
and sits there. If I drop it back into drive (auto tranny) the rpm goes
right back to hovering at 800 like it always has, and if I kill the engine
and restart it it revs properly at 800 while in park. Does anyone know what
could be causing this? the car is a '98 SL2 w/ 115,000 km on it.

TIA!!!!

Wurm

 

It sounds like your throttle body is gummed up. It costs 75.00 to fix,
but ppl on this board could probably tell you how to clean it. It may not be
your problem, but if it is,please get it fixed. My car tried to "jump" into
an intersection on a red. After it stuck twice in two weeks, I took it in.
Joe

 

Hrm, thanks for the info. I have to bring it in for regular maintenance soon
so ill check into it.

Wurm

 

Cleaning a throttle body is quite easy once you get the basic idea.
this is for the DOHC (two hamster version:

* Remove that plastic air duct thing.
* Unplug the two electric connectors - TPS and IAC. They're different
so you shouldn't be able to mix them up.
* Hold the throttle cable, and manually flip the throttle open so you
can disconnect the cable from it. The cable will 'fall' inward and
you'll hear the gas pedal thunk. It should move REAL easy.
* Pop off the clip holding the air hoses on, and slip the hoses off. Oh
yeah, do'nt lose the rubber thingie - put it safely aside.
* Grab your friendly 10mm socket, and twirl off the two bolts. The
throttle body will come off withthem, or may be slightly stuck to the
gasket and all.
* Oh yes, you need a new gasket, but if you're a cheapie like me you
might be able to reuse it. Get a new one anyway. While you're there,
get 2 or so cans of THROTTLE BODY cleaner. It's not kinder and gentler,
it's actually really a lot better at getting the junk off.
* Use a Torx, remove the TPS and IAC. Watch you don't strip the threads.
* Hose the throttle body off with cleaner, and get all the crud off.
When it's clean, it'll open/close really smoothly, and not stick.
* Wipe off the IAC pintle carefully. Don't dammage that little spring.
* Put the TPS and IAC back the way you found it. They mostly settle in
place correctly. Carefully work the throttle to make sure the TPS is on
right.
* Clean the gasket areas on the manifold and TB.
* Put the thing back together. Don't put the plastic air duct on yet,
though. Don't forget those electric connectors or the computer gets mad
at you.
* Start the car and grab can #2 of the stuff. After the second or third
try, get out of the car and connect the connectors back where they
belong like you were supposed to in the previous step.
* Follow the instructions, but the basic idea is spray the stuff in
without killing the motor by either redlinning it until it explodes, or
choking it with too much stuff.
* Put the air duct back.

Drive the car around, knowing you've now got a clean throttle body.
Your gas hopefully won't be as sticky now.

 

Having done this a few times already (old toothbrushes are standard
procedure for this job), anyone know why the thing drops back to idle once
the car has come to a full stop? I notice if you coast along at maybe 1-2
mph the thing idles high; stomp the brake and bring it to a stop and the
idle comes back down quickly.

If it was carboned up, why does stopping it alleviate the high idle problem?

Seems this happens when it get cold. Cheaper gas or more prone to
carbonizing?

BP~

 

Having done this a few times already (old toothbrushes are standard

The high idle(1200-1300) while coasting is a normal thing, not related to dirty
TB.

 

dirty TB.

Bandit, thanks for the response and your help on this board. My high idle
is around 2100 which drops to 1000-1100 when I "fully" stop. Somehow,
something has to be telling that the car is still in motion and it holds the
idle high.

I'm wondering if that pingle spring was strengthened on later models?
Wouldn't surprise me if the heat weakens it over time, or all the carbon on
it eventually wears it out.

Bent~

 

This is a 'feature'. If you roll the car slowly, the idle's high, if
you stop, it drops. I have no idea why, but it's normal. In fact, if
you roll from a stop in neutral down a slight hill, once you reach a few
mph, the idle will pop up...

 

Wow, thanx for the great instructions, with this and my Hayes im sure ill be
able to figure it out.

Wurm