2000 SL2 revs up high for no reason, is it a tranny? problem

My
2000 SL2 (automatic) started developing a frequent but not continuous
problem, a few months ago. I think it is getting slowly worse. After
being driven for 5 miles, especially in the morning traffic, it revs
the engine to about 1.5k RPM, which is about 40% higher than it should
be. So I stop at the red light just before getting to work and it
starts revving higher and higher, and then plateaus at about 1.5k RPM.
I think that is also pulls a bit, that is it seems to accelerate when
I am coasting with no gas, at low speeds, and ends up moving faster
than the average automatic transmission car.

I had the transmission fluid and filter changed about a month after
this started, and it made no difference, or maybe worsened it a bit.

I bought this thing from Enterprise rentacar, 1.5 yrs ago with about
39K miles, it ran great, and now it has about 58K miles.

I hope you can suggest what the problem is. Maybe a computer or
sensor, or the transmission computer (is there such a thing?).

Thanks a million.

Karl Kasamon
Baltimore

 

Karl,

It's not likely related to the transmission from your description. I'd
start
with a computer scan to see if any of the trouble codes are set. If you
have an Autozone near you, they will do the scan for free and if it fails
tell you the diagnostic code which could point to the source of the problem.

Based on your description and previous posters with similar problems, I'd
guess it could be a defective coolant temperature sensor (CTS). If the
engine computer thinks it is cold even when it is not then it will increase
the amount of fuel and increase the idle as it always does during warm-up.

If it is the CTS, this is a simple and cheap part to replace.

Good luck!

Bob

 

That sounds good. I'd also look for vacuum leaks and the PCV vale. On
the outside chance - if there's a good leak there, it's like holding the
throttle open a bit, and the IAC can't close enough to compensate.

Hey - take out the throttle body, remove the IAC and TPS, clean clean
clean the whole thing, and carefully clean the IAC. It might be sticky
too.

Yep. $10 and a few minutes under the hood - use a 13mm deep socket. To
get the plug off, squeeze it and pull gently. Tricky at first, but easy
once you figure it out. Don't pull the white cap part - pigtails are
$$$ from the dealer (like 30 bucks - don't ask).

With the CTS out, you can check it with an ohmmeter. But it's just as
easy to replace it.

It's not a tranny problem, in all likelyhood.

 

Wow, thank you both, very much. I will check out these leads, they
certainly sound more digestable that replacing the transmission or
something like that.

-Karl

 

I had a similar problem with my 2001 SL (5 speed).
Idle would often go to 1700 RPM.
The dealer replaced the Throttle Position Sensor and all was fine.

HTH
Rick

 

Do you have to drain the coolant to remove the CTS?

-JimG

 

Not picking on you Rick, but I've heard often the CTS is the bug. I
have the same kinda problem with my 97SL2 stalling infrequently.

But what I wanted to ask others, do you think dealers bill you for a
higher fix, do that fix, and then toss in a quick fix(without telling
you), so they're higher one appeared to work?

Not saying they don't do the more costly work, just that they suggest
that and secretly on the side do the real fix too.

Just asking....


later,

tom @ www.CarFleaMarket.com