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Random Acceleration Issue

spyderdrifter

Supporting Member
5,192
700
Jul 11, 2009
Some where in, Colorado
So I've only notice this happen over this past week. At very random times, I'll be accelerating, and it feels like my car will start accelerating itself. It only happens for a couple seconds at most, but its noticeable. The best way I can think of to describe this, is it's like keeping your foot on the accelerator pedal while engaging the cruise control. With that in mind, could this be a vacuum issue of some sort, and besides inspecting the cruise control servo, what can I look at? This happens when I have the cruise off completely. Haven't used it in over a month anyway. Anyone else encounter this?
 

troubleshoot

Probationary Member
27
0
Jul 17, 2013
Chocagoland, Illinois
Check your throttle cable and make sure its not sticking. You could take it off and try to get some WD40 inside the line and work it through. Also, your throttle body could be sticking as well. Id start there.

Ive also had the gas pedal stick under the front edge of the floor mat which makes you accelerate out of control until you hit the throttle again and pop it loose. Silly I know, but took me a few times to realize what was happening LOL.
 

spyderdrifter

Supporting Member
5,192
700
Jul 11, 2009
Some where in, Colorado
The floor mat reason is why I never have floor mats in any vehicle I own. My accelerator pedal does on occasion stick when I'm off the gas. Just haven't thought about it being related, but probably is. I'll give that a look as well as the other spots. Don't really think its the TB, since it is clean and I replaced its shaft seals a few thousand miles ago, but I'm sure itwwon't hurt to look anyway.
 

GRAVEDIGGER

Proven Member
3,620
107
Nov 26, 2007
Uniontown, Ohio
Check your throttle cable and make sure its not sticking. You could take it off and try to get some WD40 inside the line and work it through. Also, your throttle body could be sticking as well. Id start there.

Yes this ^^^. Check the cable and the throttle body. You may have to take off the throttle body elbow and clean out the throttle body. Use some type of carb/intake cleaner and clean around where the butterfly contacts the bore of the throttle body. Sometimes it gets stuff built up around there and will stick partially open, which in turn gives the symptom you are describing. Good luck! :thumb:
 

SlipknotSmoothi

Proven Member
93
63
Feb 24, 2011
Fayetteville, North_Carolina
So I want to bump on this.

I had this happen this morning for the second and third time. The first 2 times were unexpected, on the third it was because I was able to re-create it. Details as follow:

I'm pushing about 85MPH in 4th gear, about 4500RPM's. I'm not logging but it feels like I'm in about 60 to 80% of throttle. If I hold the RPM's, and shift into 5th gear, my accel position can start over, but once I hit about 115MPH and just let go of the gas, completely, it feels exactly like cruise control has taken over and trying to build to target speed. Sadly, I didn't note my RPMs for that part, as I was more concerned with regaining control of the situation.

Now, I do have a CEL for a IAC issues. I'm curious as to if my IAC is adjusting the plate due to air speed vs TPS and other variables its picking up on. I haven't managed to recreate it in another gear, yet, its only when I'm putting my foot off in it.

Some relative data:
2G AWD Manual
2.3L
20G w/ Ext gate, restricted to 8 PSI
GM MAF,
1G TB
Link V3 (Idle pin set for TPS)
No floor mats
No other accel issues.

spyderdrifter, do you have any of that in common with me? :)
 

spyderdrifter

Supporting Member
5,192
700
Jul 11, 2009
Some where in, Colorado
I may very well have some of that in common. To be honest, since this was originally posted 2 1/2 years ago, I can't say for certain if the problem ever got resolved, and I'm sure it hasn't. Most likely, I've gotten used to it happening and no longer notice. However, it's kinda funny you say you have an IAC dtc. I've been plagued with a nice variety of idle related issues for a long time. So that might be the source of the issue. Currently, my spyder has a 6 bolt (factory specs) and will be returning to 7 bolt when I complete my awd swap in the coming months.
 

SlipknotSmoothi

Proven Member
93
63
Feb 24, 2011
Fayetteville, North_Carolina
My cars throttle cable on the inside of the firewall was really rusty and made the pedal rock hard. Try spraying down the throttle box, and the grommet I side the car with some lithium grease or wd40

I' not going to dismiss this as irrelevant, but I would think that cable would stick many more scenarios than only the one I can get this to happen in. Unless, some how road conditions and engine movement at 115MPH is the only way to get the cable to stick ....
 

SlipknotSmoothi

Proven Member
93
63
Feb 24, 2011
Fayetteville, North_Carolina
I may very well have some of that in common. To be honest, since this was originally posted 2 1/2 years ago, I can't say for certain if the problem ever got resolved, and I'm sure it hasn't. Most likely, I've gotten used to it happening and no longer notice. However, it's kinda funny you say you have an IAC dtc. I've been plagued with a nice variety of idle related issues for a long time. So that might be the source of the issue. Currently, my spyder has a 6 bolt (factory specs) and will be returning to 7 bolt when I complete my awd swap in the coming months.

In the coming days, I'll pull a log with Link and see what the IAC and TPS is doing. That should help, I think.
 

SlipknotSmoothi

Proven Member
93
63
Feb 24, 2011
Fayetteville, North_Carolina
A faulty IAC can cause all kinds of weird behavior. If this is for a 2g I have a working CC system if you want to try swapping it if all else fails.

Let me get a bit more data and t-shooting done, first. If that turns out to be whats needed, I may very well take you up on the offer. Hopefully I can do that today.
 
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