Replace manifold with APN

Alrighty, I just replace my exhaust manifold with the APN. Everything went on smoothly, but now I have a VERY high idle. I read the other threads addressing this issue, but nothing has helped. I adjusted the TV cable and made sure everything is properly connected. I had the battery disconnected throughout the entire process, so, the computer should be cleared...correct?

I did notice a wierd thing though. When I pull on the throttle lever and release it, I hear something like a thunk coming from inside the housing of the middle cable. Is this normal?

I am short of ideas and do not feel like taking it to the dealer..

Help!

Sounds like a vacuum leak. Either the intake manifold is leaking or a vacuum line was left diconnected or was damaged during the install (they get old and fragile, especially the plastic lines).
The idle RPM may help narrow it down some. The smaller vacuum lines left disconnected often cause a moderatly high 1000-1200 RPM idle, the brake booster line 2000 RPM.
Check to see if the throttle plate is closing all the way, there could be a kink or hitch in the throttle cable or something causing the throttle plate to hang open a little (or hesitate). You might want to look down the TB throat (with the motor off) and have somebody work the throttle and see if it has a hitch or hesitation, when the throttle is released (graphit or other dry lubricant is your friend, oil or grease is to be avoided when lubricating cables). The throttle plate should just touch the inside of the TB throat or have a very small gap, the stop is mostly to keep the plate from slaming into the TB wall, when the throttle is released. It's always best to avoid sharp bends in the TV and the throttle cable (and the speedo cable).
I haven't seen it often, but have seen a frayed cable, just one or two broken wires, that cause the cable to hang inside the sleeve or at the sleeve end.
Check and see if some carpet or padding is jammed up near the gas pedal, sounds dumb, but happens more than you'd think.

Thanks for the reply! My throttle is about 1500 in Park. In Drive, it drops to about 1100. All of the vacuum hoses are in good shape. I think my intake manifold may not be snug. Time to remove everything and do it all over again I guess. Is there an easy way to tell if the intake is flush against the engine. It is hard to tell. Thanks!

Make yourself a set of plugs for the vacuum outlets on the manifold, a small piece of the right sized tubing with a screw or bolt in the end. The motor doesn't need any of the vacuum hookups, to run. Except the MAP hookup at the TB. Check and see if your TB is snug and if you reused the old TB gasket the compressed part of the gasket is seated in the orignal posiition.
Remove the intake as a last resort, just too much work before checking out the other possiblilites.
If you have to reinstall the intake, torque the bolts from the middle out. If you want to see how the gasket is seating, you can coat both sides lightly with copper paste (doesn't hurt a thing and may actually help with the seal), tighten the bolts and remove it and look, you can see the low spots, if they are serious.
I have a large piece of iron flat stock, like 6 inches wide a half inch thick and a yard long, I use to see how flat the exhaust manifold is before reinstalling. I also clamp the exhaust manifold to it, before welding up cracks.
If there is much of a leak around the intake manifold the motor will often change RPM's if you spray some water around the intake where it seat to the block (with the motor cold) just after starting. I use an old widow cleaner pump sprayer.

Thanks everyone. I actually took everything apart and reinstalled it. Turns out, the intake manifold was about a 1/8 of an inch to low on the block. I sprayed some copper sealant on both sides pf the gasket as well and everything went together without a hitch. This time around, the entire job only took about 2 hours

Anyways, problem solved. Just an FYI, the APN header does work with the 99+ intake manifold WITHOUT any modification. I have read in some instances, that both the intake and exhaust manifold needed some "grinding" to mesh properly. In my case, this was unneccesary.

Again, thanks to all for their suggestions!:thumbsup:

okcjeeper said:

Anyways, problem solved. Just an FYI, the APN header does work with the 99+ intake manifold WITHOUT any modification. I have read in some instances, that both the intake and exhaust manifold needed some "grinding" to mesh properly. In my case, this was unneccesary.

Again, thanks to all for their suggestions!:thumbsup:

Click to expand...

hope i get that lucky doing mine, is there a rule of thumb for clearance between the two manifolds in the tight spots?/how close their allowed to get? you probably wouldnt want them touching cause of noise and vibes right?