Missing throttle return spring?

Steve Rodgers

TJ Enthusiast
Joined
Mar 25, 2018
Messages
355
Location
Maui, Hawaii, USA
4B1EFDC5-0D9C-4821-97AA-89156405DA27.jpeg
attached is a photo of my 97 SE 2.5 throttle body linkage. My finger is pointing to an unused connection. Is there supposed to be a return spring there?
I ask because it sometimes settles back to idle very slowly and I have to tap the gas pedal.
Or is it time to check the idle air control valve?
 
The main throttle return spring is on the throttle body valve plate shaft where it's not easily seen. You might have a sticking/dirty IAC which can be cleaned by spraying throttle body cleaner into the air intake while the engine is running at idle rpms. Don't raise the rpms, the IAC only draws air (and thus the sprayed cleaner) in through itself at idle rpms.
 
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My '04 4.0 doesn't have one either and I don't think it ever did.

My 05 didn’t either, thought I read somewhere that the extra spring disappeared in the 04 time frame. I ended up buying a Mr Gasket set of springs and copied the earlier TJs. My gas pedal was touchy off-road.


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Yesterday I did the Throttle Body and IACV cleaning thing with the engine idling. I slowly puffed the cleaner into the IACV intake port in the top of the throttle body. It tries to stall the engine so I kept puffing it slowly in. I'll know over the next few days if my idle returns to normal. It looks like mine may have had a return spring at some point but that may just be a holdover and mine may never have had one. It's a 97 TJ 2.5 stick. So far so good, it idled fine after the cleaning. If the problem returns I'll remove the valve and clean it more thoroughly to see if that helps. I'll need to be prepared to replace the gasket if I do. I think it's the original valve or at least it looks as old as the surrounding parts.
I don't know what's in throttle body cleaner but it sure melts the grime away in there!
 
Spraying enough cleaner into the throttle body at idle rpms to actually stall the engine is fine, it's actually good to do so as that gives the cleaner more time to soften the crud inside the IAC and orifice in the TB the IAC's plunger fits into while you get inside the Jeep to start the engine again. My engine dies 8-10 times whenever I'm cleaning the IAC, I just restart it and spray more cleaner into it using at least a third of the can in the IAC cleaning process.
 
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my rpms stick, even while in gear. if a depress the clutch the rpms will stay there, or it's like i have cruise control on (toyota crawl control) if i remain in gear. when i tap the gas, it drops back down to normal. I've cleaned my iac and it got better, but not for long, and now it happens A LOT. new iac maybe?
 
my rpms stick, even while in gear. if a depress the clutch the rpms will stay there, or it's like i have cruise control on (toyota crawl control) if i remain in gear. when i tap the gas, it drops back down to normal. I've cleaned my iac and it got better, but not for long, and now it happens A LOT. new iac maybe?
Did u ever figure out a fix?
 
my rpms stick, even while in gear. if a depress the clutch the rpms will stay there, or it's like i have cruise control on (toyota crawl control) if i remain in gear. when i tap the gas, it drops back down to normal. I've cleaned my iac and it got better, but not for long, and now it happens A LOT. new iac maybe?

Mine started doing that, traced down all of the vacuum lines, replaced the IAC etc, turns out it was a leaky intake manifold gasket.