Slightly erratic idle after Cobra Intake Install - normal?

[Stanger007]

I installed a cleaned up Cobra intake I got from super302 this weekend.

After resetting the ECU I started the car, checked for fuel/coolant/oil/vaccum leaks and reset the timing back to 14*. It idled noticably rougher - the engine moves side to side ever so slightly. I drove it around for about an hour today and the idle improved slightly but is still just a little rough.

In park (automatic) it idles around 1000rpm and in Drive it idles around 700. This is just a touch higher than where it was with the stock intake. Is this slightly rougher idle normal after swapping intakes? My mods are below.

I checked all the vaccum connections for leaks, pinched off all the vaccum hoses I could while the car was running. I also sprayed some starting fluid around the front of the intake (all I could get to) w/ no changes in RPM speed. The only hissing I can hear is coming from the little canister that sits by the EGR on the firewall that has vaccum coming into it from the bottom of the intake. Not sure if this is normal because I never listened to it. The PCV valve is also seated well into the grommet with the screen in place.

The rough idle is definately livable if this is the way it is but I'd like to know if I need to pull the intake and glue it down again.

This is my third intake to install. The only thing I didn't do on this intake that I did on the others was when I stuck the intake down I didn't use any guide studs and I used the rubber end pieces instead of a bead of RTV. I *did* put some blobs of RTV at each corner of the end gaskets but I didn't let it sit longer than a minute before I put the intake down. The end piece gaskets look seated just fine when looking at them with a mirror (back ones) or from the front.

On another note, the car caught second pretty well getting on the Interstate (never done that before)

Thanks!!!

 

[wytstang]

It should idle like it did prior to the swap. It should idle in park at about 700rpms not 1000rpms.

 

[S/CBlack95GT]

My car would die all the time after I swapped intakes. I had to go through the idle reset process and after that it ran great with no problems.

 

[luke_ftw]

how do you reset your idle?

 

[Stanger007]

how do you reset your idle?

Here's a good link on how to reset your idle.

I haven't cleaned the IAC or reset the TPS yet but the other stuff I have done w/ no change - I've still got an uneven idle. I didn't remove the IAC or TPS from the throttle body when I did the intake swap so none of that should have changed. I'll go ahead and check them today however.

 

[stprorolla49]

well i did a PI intake swap on my friends 98 with him this weekend.....the same thing happened with his, we got everything done and started it, and it started fine, but it had an erradic idle on one side....the idle was also around 1200 rpm when we went to the back of teh car and felt the exhaust pulses, the driver side tailpipe had pulses that were very spread apart....so we check all of the injectors, and pushed them down harder, and checked all the connections between the injector, and the electrical connector, and sure enough when we pushed in the connector a little more on teh #6 cyl, the motor gave a little spurt noise, and then everything was running fine....check all your connections over and over.....good luck man

 

[dstanggt50]

My idle was a little off after my gt-40 install, but all I had to do was mess with the idle screw on the t/b.

 

[super302]

I installed a cleaned up Cobra intake I got from super302 this weekend.

THATS ME

 

[mo_dingo]

Get a vacuum gauge and check your vacuum. Also check all of your connections and make sure nothing is loose.
Scott

 

[MustangGT95]

Here's a good link on how to reset your idle.

Thanks for the link! When it says to disconnect the wire from the idle module or whatever does that mean the IAC?

 

[Stanger007]

Thanks for the link! When it says to disconnect the wire from the idle module or whatever does that mean the IAC?

Back from the dead! You are correct - the IAC is the idle motor.

To answer the problem above, my idle problem above ended up being a vaccum leak in the intake itself - a little JB Weld cleared it right up.

 

[MustangGT95]

Was the intake cracked?

 

[Stanger007]

It had been opened up to be ported before I bought it and hadn't been closed correctly.

 

[MustangGT95]

Did you notice a difference with the new intake? I might pick-up a GT40 intake this weekend to install on my 95.

 

[94tang]

mine idled higher (650 to 800) after the cobra intake install,but wasnt "rougher"

 

[JJ95GTID]

I would give it a week or two to give the ecc some time to learn the new part. As for the blue rubber gaskets at the front and rear of the lifter valley I would take them out. Mine split right down the middle of both gaskets and cause an oil leak out the rear. I thought I had a rear main seal leak until I put the Explorer intake on using a thick bead of rtv instead of the gaskets. No more leak.

 

[Stanger007]

I had more topend after the swap.

One of the Mustang mags ran a comparison of the GT40 and Cobra intakes vs some of the newer ones... the Cobra and GT40 held their own... not too bad for stock pieces. With a little porting they do quite nicely as well.

I'm not sure on the GT40, but on the Cobra, the stock shocktower brace will not fit. Gotta go aftermarket if you want to still have one. I removed mine and did not notice a bit of difference but YMMV.

 

[lamrith]

What abouy an explorer piece, will it fit with the strut brace?? I already have an adapter elbow, just waiting for get an upper to match my lower...

 

[MustangGT95]

I don't even have the STB on anymore. No point IMO.

I threw the little blue gaskets away and used RTV. But I somehow managed to screw up my intake install pretty badly. Front and back are still leaking. I've done a bunch of SBC intake installs and never had a leak. I try it on a ford and I didn't help anything lol.

I should probably go ahead and get the intake. I know my e-cam wants to breath higher than 5k. Which is about were my power is cutting off now. I guess I'll have to postpone my offroad H pipe for 2 more weeks.

 

[JJ95GTID]

What abouy an explorer piece, will it fit with the strut brace?? I already have an adapter elbow, just waiting for get an upper to match my lower...

No the stock GT STB does not fit with the Explorer. It is a good intake though. It was my last upgrade. With just the intake I went from a best of 14.469sec ET to 14.103sec ET at the track where the weather was very similar.