Mod nightmare: help please!

[Mwynn]

Had the car for 7 months now... drive it, track it, love it!!! Installed Bobs oil seps on both sides around 500 miles, no issues, caught a lot of oil. So... last month once I hit 5000 miles I bought some basic mods from lethal. JLT cold big air kit, Ford racing twin 65mm throttle body, Lund tune with SCT scanner and JBA off-road pipe (which I had to replace with an American made MRT pipe, got a whole thread on that crap).

Anyway, I have a drivability problem since I have installed these parts. Under deceleration letting the gears do some braking I have a HIC-UP in the throttle. When decelerating under moderate to light load say from 3000 rpm to 1000 rpm (not touching the gas pedal) the motor surges with throttle a bit as if someone bumped the gas pedal, it happens anywhere between 1800 and 1200 rpm. The car lurches forward for a split second. Its a very noticeable lurch.

I contacted lund, they sent me another tune. The problem is still there. Contacted them again. May be a vacuum leak? Ok, took the intake off and re-checked everything 3 times including all connectors, hoses, and such. I don't know at this point what it is causing this? Bad throttle body? Help please... thanks

 

[Chris!]

Sounds similar to other problems here- usually was either the tune or the TB.

I'd swap out the TB- if not- it's gotta be the tune

Hope you get it squared away

 

[T3RMIN8TOR]

Try pulling the filter all the way down and making sure the tube is tight against the throttle body. I had the same issue a few months ago but adjusted the filter and intake tube and it seemed to do the trick as well as the computer relearning itself. BTW, I have the monoblade which some claim to have less driveability but no problems here. I know how you feel, good luck!

 

[Mwynn]

Ok, I will try that...

 

[Devious_Snake]

also for shits and giggles, remove the ram air tube from the front of the grille that connects to the airbox, see what happens

 

[Van@RevanRacing]

Just pull the air filter down and make sure the tube isn't butted up against the throttle body.

 

[Mwynn]

tried moving the air tube close to throttle body... did not work.. problem still persists. ugh!!

 

[Van@RevanRacing]

Move the tube away from the throttle body and pull the air filter down to the end of the intake and rotate it 45 degrees. What are you plugs gapped at?

 

[Mwynn]

Hey van... I have tried putting the air tube 3 different ways, butting up against the throttle body, an inch away from throttle body, and 2 inches away(max)... no use.

 

[Mwynn]

Stock plugs... I ordered some NGK tr6 from you today... put my email in wrong... send them up to GA anyway...

I will try the air filter rotate.

 

[Van@RevanRacing]

Plugs are going out tomorrow via USPS.

Gap them at .030

 

[Myfast70]

Isn't there something that has to be ground down slightly to get the TB to sit flush? At least that's what a local buddy of mine had to do to his.

 

[Blackdevil77]

I say try the stock throttle body and try again. I bet it has something to do with that, the tune, or the combination of the two.

 

[BOD89LX]

Do you have the updated air box and filter?

 

[humilde]

i had the same issue than you , but with the stock intake and the 65mm throttle body,
the throttle body has a small screw in the top right of the tb, you need to unscrewed until you see that the idle rpm goes to .700 rpm. in my case i need 1.5 turns , i did this with the engine started.

with your engine started in the gauge mode put the voltage gauge , you will see that its moving from 13.9 to 14v rapidly , when your are unscrewing the scrw you will see that it will remain in 13.9 constant.
(this fix my problem in my car , mine is a 2013 gt 500)

the stock throttle has the same screw , check that you have similar turns in the 65mm .
in my case i did have to do 1.5 turns more than stock TB.

 

[Mwynn]

Tried rotating the filter... no luck. I do have a aftermarket filter and box which came with the big air kit. This sucks. Its most likely the throttle body, is it supposed to sit fully closed when the car is off? I will try the stock TB tom.

 

[Van@RevanRacing]

These tunes are very repeatable. The anomaly is parts. What's not cooperating? Someone suggested trying the OEM TB. Try that step next.

Double check all connections with the oil separators and make sure nothing is letting air in after the MAF. I had an instance where the separator wasn't connected entirely and another where the can was not tightened entirely.

I've also had instances where the plugs fixed everything because the plug gap on the OEM plugs was off on all eight cylinders.

 

[Mwynn]

Ok... I will try the stock TB in the morning... will It be ok to run it with the lund tune? Just taking it easy to see if the problem occurs.

 

[biminiLX]

Sounds like you need a dyno tuning session and once over at a good performance shop.
With the more advanced ECU and wide-band O2s its not as important as in the past, but your issues sound like you need some datalogging and diagnostics of the parts for installation issues.
Looks like you're in GA, maybe look up Bob Kurgan?
Good luck.
-J

 

[paulsauto]

I'm in ga too and also have a 13 with same mods except stock throttle body mine runs fine I also have an Ids if you need some data logging I'm in south ga bout an hour south of Macon.