surging idle help

[Jwood562]

2008 mustang gt, 66k miles, original owner.

previous engine mods, roush intake, roush axle backs, bama 91 octane tune.

car ran perfect and has never had an issue.

so i went to install steeda under drive pullies and do a coolant flush/ thermostat at the same time. removed the throttle body to get the thermostat housing, everything seemed to go smoothly, put it all back together and started her up. I was letting it idle to bleed the coolant system and as the engine got warmer it started to surge idle and even stalled once.

no CEL codes

seems like a vacuum leak, So I double checked the intake and nothing.

The only thing I can think of is the throttle body gasket, it came off when i removed the throttle body and seemed to be "stretched" as it was difficult to put back into place.

Also as i shut the engine off, besides the "woosh" from the intake, I can hear another "woosh" sound but cant pinpoint where its from.

Anything else I should be looking for?

Do the pullies require a tune?

 

[Dino Dino Bambino]

No, the pulleys don't require a tune but you might want to replace that throttle body gasket though.

 

[Jwood562]

yeah that was my first thought, i bought a new throttle body gasket and will do it soon.

I thought I would ask if there is anything else I should look out for. I am very meticulous when working on my cars and this is throwing me off. Im upset at myself for not having a new throttle body gasket on hand as it didnt cross my mind when planning this upgrade maintenance.

 

[JC SSP]

Change the TB gasket and make sure the Roush intake tube is secured to the TB. I have seen where the band clamp gets off-set and does not tighten equally around the TB or even the tube.

Also, take a look at the TB blades and make sure there is no obstruction, and they are fully closed. Leaves, paper, debris could keep them from seating properly.

 

[07 Boss]

Did you clean or mess with the TB at all? It is my understanding that manually moving the blades should be avoided. Not sure why but that is what popped into my head.

 

[Jwood562]

i didnt mess with the throttle body at all, i heard the electronics on them are sensitive so i didnt mess with it and didnt even clean it. removed, placed to the side, finished thermostat work and replaced.

headed out to change the throttle body gasket, i will report back

thanks for the replies

 

[Jwood562]

back with good news and a my tail between my legs.

went to install new throttle body gasket, began taking off the intake. removed the filter and I looked up the intake tube toward the air flow sensor and saw daylight. I somehow managed to pinch the intake coupler from the tube to the box. after carefully fixing all the intake couplers the car runs like new again.

took it out for a good 20 min test drive and shes back to normal.

thanks for all the help

anyone want a new felpro throttle body gasket?

 

[Dino Dino Bambino]

anyone want a new felpro throttle body gasket?

Save it for a rainy day. It might come sooner than you think.

 

[JC SSP]

Ahhh it’s the simple things in life…