Idles at 3k rpm NEUTRAL cant stay under 45mph!

[RogueSteel]

1989 Turbo Auto Targa with K&N, 3" DP, stock cat, Blitz Nur Spec II and a Manual boost controller

Drove the car about 180 miles last night at an average speed of 80 MPH on cruise control, when I finally got in town and tried to stop for a light i had to mash the break pedal to the floor to stop and hold the car there (in Drive) while waiting for the light to change, It was revving to 1.5k RPMs and as soon as I let go the car pretty much launched into motion. Then when I arrived at my destination I was going to let it "idle down" before I killed it but when I put it in park the tacho shot up to 3k and stayed there until I killed it.

I've got to head home sunday night and really need help with this, asap please :3d_frown:

(boost is at about 7 psi)

 

[airhead04]

Have you checked the throttle linkage? Possibly something os stuck or snagging it just right?

 

[AcIdBuRn02ZTS]

That or a vaccum leak... check major vac. lines...

Also... make sure the cruis act. isnt stuck which would hold the throttle open

-AcId-

 

[jetjock]

It can't be a vacuum leak. As pointed out check for throttle restriction. Cable, dashpot, CC actuator, etc. Also check timing and see if the ISCV is full open...

 

[RogueSteel]

Checked a couple things (next day) and now its down to about 1100, i'll keep you posted

 

[speedgilligan]

check to make sure the TPS is still aligned properly, it may have slipped

 

[arknotts]

Take it to the dealer for the "unintended acceleration" recall?

In all seriousness, like mentioned before I guess the throttle cable/linkage would be the first place to start.

 

[ae86ma70]

I had this problem a couple of times. My throttle body has a hex screw adjustment for the throttle valve adjustment. The screw works its way out of adjustment and keeps the throttle valve (butterfly) from closing as it should. As a result, it's all you can do to keep the car stationary at a red light. I ended up removing the TB, adjusting it back to spec, and putting a little BLUE threadlocker on the adjustment screw so that it would stay put. I've not had any problems since. Hope this helps.

PS: At first I thought I had a bad IAC or that it was a TPS problem, but no codes were being displayed.

 

[ae86ma70]

I say IAC. In Toyota parlance, that equates to Idle Speed Control Valve, or ISCV (just as jetjock mentioned above).

 

[tmaxx31190]

i had a similar problem with my 91' with a manual tranny. I had just got on the freeway and really put my foot in it (to get up to speed. cough, cough) lol. then i had a red light coming up and i had to slow down, so i let off the throttle and pushed in the clutch and my rpm's rapidly rose to about 5k! this scared the crap out of me so i hit the throttle pedal a few times with my foot and the rpms returned to normal. once i got home i let the turbo cool down and shut the car off. once it was quiet in the car, i slowly pushed the throttle pedal back an fourth and was able to hear a binding noise, almost as if the throttle cable had a worn spot on it and it is was unwinding a little bit. now i know the throttle cable was my problem, but you might just try and listen while you sit in your car and see if you hear that binding noise. a throttle cable from the dealer is about $60. good luck finding ur problem

 

[TomFraser]

if you find a fix for this please post it, I've had the same issue (idle only at about 2400 though) and it was not my throttle, and not my TPS, i'm replacing the IAC now to see if that does it

 

[RogueSteel]

I let it sit overnight and it pretty much returned to normal, when it was idling (1300rpms) high i pulled the throttle closed in the engine bay and that stopped it.

So in my case i think it was the cruise act and the throttle return spring.

 

[Poodles]

Or, the throttlebody is dirty, or the linkage on the valve covers is sticking.