Throttle Seems Like it is getting Hung Up?

[G. Wiffington]

So ever since I replaced my motor mounts I now have an issue with what seems to be regarding the throttle. I feel like I did something when I was putting in my rear motor mount. I only removed the throttle body & my SRI when I did this job.

When I blip or slightly hit the Gas Pedal or the rotor on the throttle body it has a delayed rev. It revs but almost seems like it wants to rev twice? Seems to do that at only low RPM revs. But, also when I am leaving first gear from a stop the throttle literally gets stuck to the point where I am hitting the brakes & the car still wants to rev up. It only stops when I step on the clutch then the RPMs jump up a tiny nit then levels back out.

It is weird because the idle is PERFECT. It is not jumping or wandering all over the place. It is just when I slightly hit the throttle it has a delayed rev & while I am moving the car wants to keep going like I am giving it gas even after I let off the throttle.

I inspected all the vacuum hoses to double check there are not leaks (used throttle body cleaner & sprayed everywhere but did not have a change in idle or no idle jumping.) I retraced all vacuum lines back to their existing locations & they are all correctly hooked up.

I also checked the throttle cable to see if there were any frays or breaks on the cable but it looks good & moves good. It is also new-ish from last summer.

I had an extra Throttle Body with TPS intact but even after I scrubbed it spotless the extra Throttle Body gave the same symptoms as the original Throttle Body.

I replaced a hose that ran from the IACV to the FITV because it was somewhat swollen & tattered looking but that made no difference. I even clean the hell out of both FITV & the IACV & still has the same exact symptoms with the throttle getting stuck.

I also switched out my P12 ECU & put my original back in to see if it was the ECU not recognizing something but there was not a difference. Same exact symptoms.

Only thing I did notice was that shortly after shutting off my car there is a hissing sound coming from the driver's side of the Intake Manifold.

Did the Intake Manifold Gasket spring a vacuum leak? Or did I maybe rip a coolant line in the process of doing my rear motor mount? I was somewhat rough putting the mount in because after a while it was a pain in the butt to maneuver.

[h22sparkle]

The throttle plate is gummed up/by gunk and carbon soot .You need to spray some throttlebody cleaner and play with the plate a littlebit to make sure it doesn't get stuck. A little bit of wd40 will help.

[s2cmpugh]

You mentioned you replaced the throttle cable. This to me would be the first place I would check as you've covered most of the other possible causes.

What was the quality of the cable replacement? Does the movement of the gas pedal feel smooth from idle to full throttle? Check the gas pedal mechanism itself to see if anything is binding or not correctly attached. Maybe a piece of debris got caught somewhere and is causing this issue around the gas pedal area.

If the cable was replaced with a poorer quality unit, consider OEM.

[G. Wiffington]

You mentioned you replaced the throttle cable. This to me would be the first place I would check as you've covered most of the other possible causes.

What was the quality of the cable replacement? Does the movement of the gas pedal feel smooth from idle to full throttle? Check the gas pedal mechanism itself to see if anything is binding or not correctly attached. Maybe a piece of debris got caught somewhere and is causing this issue around the gas pedal area.

If the cable was replaced with a poorer quality unit, consider OEM.

Yes it was replaced last summer but, I think I could rule out the cable. I preformed a test where I started the car without the cable attached to the rotor on the throttle body, then revved the car up from the rotor itself but still gave the same results. Only does it when I rev it slightly or a real quick flick of the rotor.

[G. Wiffington]

The throttle plate is gummed up/by gunk and carbon soot .You need to spray some throttlebody cleaner and play with the plate a littlebit to make sure it doesn't get stuck. A little bit of wd40 will help.

Yeah, I have two different throttle bodies & scrubbed inside & around the butterfly until they were spotless. I used a toothbrush & throttle body cleaner.
Both throttle body's with different TPS's & still give the same exact symptoms.

[G. Wiffington]

Another way to describe my issue is when I am driving in any gear at a low RPM. For example, my neighborhood roads are pretty skinny so I do not want to drive fast. So, I will usually slowly cruise through in 2nd gear & the throttle will literally stick until I grab the clutch.

But, if I down shift into a lower gear with a higher RPM there is no issue?

It really sucks when I am trying to back up because the throttle gets stuck when I give it gas. My neighbors probably think I am some jerk who keeps revving up his car real loud ahah.

I'd rather not ride around in a lower gear with the RPMs screaming just so the throttle won't stick haha.

[dj_ender]

Did you bleed the coolant system after you replaced the coolant line from the IACV? If not, that may week be an issue, or THE issue. If you're getting hissing after killing the engine, and it's not coming from the intake tube, you probably have a vacuum leak.

[G. Wiffington]

Did you bleed the coolant system after you replaced the coolant line from the IACV? If not, that may week be an issue, or THE issue. If you're getting hissing after killing the engine, and it's not coming from the intake tube, you probably have a vacuum leak.

Yes but, not the way our cars are supposed to be done with the bleeder valve. I just did it the old fashion way with the radiator cap open & let the car run until the fans come on & any bubbling at the radiator top has stopped.Ever since I got the car the hole where the bleeder valve is screwed into has been clogged up with some residue buildup I guess. I know I need to take the thermostat housing off & drill out the hole to clear to obstruction. But, I never had this "throttle sticking" situation.

But, the hissing sound I was talking about was not present before I did my rear motor mount job. The hissing happens about 15-30 seconds after the car is off. It is not coming from the throttle body area. It sounds like it is coming from under the air boost valve.(I have the air boost valve capped off.) This is why I thought maybe the Intake Manifold Gasket was leaking. But, I used throttle body cleaner to spray around EVERYWHERE but there was not spike or change in the RPMs or idle position.

Could a cracked or old coolant hose cause this to happen to my throttle? That's what I was thinking, maybe?

Today after work I am going back to re-clean the FITV, IACV, & throttle body.

I want to test my MAP Sensor because I know that is a key component with Manifold Air Pressure <-lol. Actually, I did move the Black Control Box somewhat out of the way when I was doing my rear motor mount.

Everything was great with the idle & throttle before I did my rear motor mount. (& no I do not have an automatic with the vacuum line going to the rear motor mount.)

[G. Wiffington]

Re-bled the coolant system, installed a brand new FITV, & adjusted my throttle cable to get all the slack out of the cable. I also replaced the bypass inlet hose. This hose had a nice 1 inch tear underneath as well as the hose being swollen & feeling frail to the touch. It feels better than before with the throttle getting hung up but not quite 100%.

So weird because if I am just shifting into 5th gear & at a low RPM I can feel the car pushing itself to go still & I can hear the Intake sucking in air.

Haha oh yeah & sometimes putting it in reverse is hilarious because the throttle gets hung up & I am flying backwards! Too fast backwards is funny/dangerous!

[Rilas]

Once installed on the car how does the butterfly in the throttle body feel when you rotate it? Smooth is there a catch somewhere? Also have you played with the articulation of the rotor while the intake tube and everything is off to watch the throttle plate in action? Is there something dumb stuck in the intake tube that is somehow messing with the butterfly plate?

It's just so weird that your experiencing this. That's why I'm asking all the dumb obvious questions. Since you've seem to already done everything that should have taken care of the issue.

[G. Wiffington]

Okay well the original TB that came with the car was taken off because I had a loaner car to get another TB from which is the current one installed. This is what confuses me because both throttle bodiess have the same exact problem. Both had separate TPS as well.

It is very smooth but I did notice that the rotor, right before it closes somewhat "clicks". But, the click I am hearing is the throttle cable moving horizontally on the rotor. Like I can see the cable will shift a little towards the rear of the car right before it closes. Around 2mm of movement it makes right before closing. Do you think I have still a tiny bit of slack in the throttle cable to the point it's getting hung up??

& again this all happened after I re-did all my motor mounts.
I checked all the grounds & even cleaned them up by sanding down the mating surfaces to give better contact.

[oni_cb7]

Did you tighten down each of the motor mounts as you put them in? Or, did you leave them loose and tighten them once they were all replaced?

[Fleetw00d]

Do you think I have still a tiny bit of slack in the throttle cable to the point it's getting hung up??

There is SUPPOSED to be some slack in the cable. According to the OEM service manual, with the throttle completely closed, there should be 0.39 - 0.47 inches of deflection of the throttle cable near the throttle linkage (cable pulley on the throttle body).

[CornDog]

What about your brake booster? Have you checked it? Thats the first thing I think of when you say it still hisses after you shut it off. That thing holds a lot of air. Cap it off if you're unsure. Don't drive it like that though...

[G. Wiffington]

Did you tighten down each of the motor mounts as you put them in? Or, did you leave them loose and tighten them once they were all replaced?

Put the front in then the back mount & tightened them up. Then put in the tranny mount then the driver's side mount then tightened both.