4 sec. rev down?

[mlatten]

Under no load, my 3.0 takes 4 FULL seconds to go from 4k rpm to idle. This just seems really long, and I have a hard time banging out quick shifts because of this delay. I takes forever between all shifts, really. This only started about 6 months ago, as it used to drop straight to idle from any RPM - great for fast shifting.

I've cleaned my IAB fiercly and have no codes to share?

Is this normal, or should I investigate further (gas milage is pretty much the same as always).

Thanks for any input.

Matt

 

[Methos]

TPS maybe? My only thought

Methos

 

[thecrew2999]

yeah TPS would be where i would start

 

[mlatten]

Just changed it w/ a new one about fifteen minutes ago (Motorcraft).

Same bananas. But she runs, and that's all I can ask for.

Thanks guys,
Matt

 

[SHO#7]

What did you clean your Idle Air Control motor with.

Carb cleaner will melt the insides.

Mike

 

[syP]

time for a lighter flywheel

 

[SHOtime2511]

try reseting the EEC,now that you have the new TPS.

 

[Racer X]

What did you clean your Idle Air Control motor with.

Carb cleaner will melt the insides.

Mike

Oh noes!!! Tell me you're not serious!

 

[mlatten]

I just used a lot of electronics cleaner on each part that I broke down along with an old toothbrush.

Thanks for the advice. I disconnected the battery for about an hour and when I fired her up I did followed the instructions to reset the idle. Still does it.

I look at it this way: even though I have no codes . . . at least I don't have any codes. lol

Thanks again.

Matt

 

[thecrew2999]

yeah carb cleaner i used some on cleaning my intake before and it melted the toothbrush i was using. so i dont recommend in on plastics

 

[Shoaz]

You might also check for vacuum leaks, in this case, a very small one.

The Pumpkin has a weird problem with intermittent high idle, and it's usually the vacuum plug that I put over the EGR port (since the EGR hardware is gone). For some reason the car eats those plugs and they disintegrate and leak after only a short while...but I don't think that's the entire problem so I'm interested in what you find as well. I'm already thinking I need to go through the IAC and the TPS.

 

[mlatten]

Hate to be a part swapper but I had a few hours between classes and tried some things. Changed and retried the vehicle after each part, no changes noticible. Coil pack, DIS, BCM (the black relay box mounted to front of engine bay w/ 4 screws, right?), swapped on another intake w/ its own IAC. Car makes all the same sounds and revs the same.

I cleaned the MAF w/ electronics cleaner (let it soak on). Since it's an MTX, could these be symptoms of a failing MAP sensor? Would that throw a code?

And unfortunately, no signs of a vacuum leak, and I've checked and sanded most grounding points.

Thanks again,
Matt

 

[jelloslug]

Does it seem low on power? A clogged cat or another restriction in the exhaust could make it rev down slower.

 

[somedude_001]

Oh noes!!! Tell me you're not serious!

well that explains why mine is throwing a code now

here is a super quick way to tell if its the IAC. start the car let teh idle settle down to normal (800~) then unplug it while the car is running. now drive the car and see if its any different.

i'm in buffalo NY I have a known good IAC if you want to try swapping it out be my guest. i'm not offering to give it to you but your welcome to try it.

 

[mlatten]

Well the cats don't glow after driving, or rattle when smacked - so I'm taking them to be OK.
As far as power, well, long story, but it turned out last week that my timing belt was set one tooth off on the crank (ATX timing on an MTX) for the last year. I had plenty of top end, but no torque. Thanks to these archives though I remedied that, and she's better in that respect, but still had the long rev down. I thought the CPS was bad too, but it turned out the pulley and gear had walked out about a quarter inch due to a loose bolt - really loose

I'll pull the y-pipe anyway and use a shop vac to investigate tomorrow.

Have we ruled out the MAP sensor?

Thanks as always,
Matt

 

[NotSoSlowSHO]

Something else that has yet to be mentioned....

VSS

I chased my tail trying to fix the same problem, only to find the speed sensor was the culprit.

 

[mlatten]

Would a VSS throw a code / would it slowly go bad or is it totally gone once it's done? At least it's an easy fix!

Matt

 

[gmorrell]

VSS drives some return to idle strategies when the vehicle is moving. Quick VSS diagnoses: Does the cruise control function?
There are some IVSC quick tests as part of KOEO, but they don't test the VSS, and I don't recall any VSS-related codes, so I don't think it can throw a CEL if it's ****-up. (IVSC = Integrated Vehicle Speed Control; means that cruise functions are integrated into the EEC, instead of a separate control module.)

 

[NotSoSlowSHO]

When my VSS was going bad, the cruise did still function, but it "trailer-braked" a bit.

No code was ever thrown.

All I had was that annoying haning idle when coming to a stop sign or red light.

 

[mlatten]

Cruise works, and I don't have any wierd braking issues. It's an easy fix for the MTX; maybe I'll go grab one.

Thanks again,
Matt