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New rebuild, working out bugs.

At about 2,000 rpm, car feels like it is missing. Not spitting and sputtering, but jerking you can feel thru the seat of your pants.

My buddy brought over gizmo he made up for checking for vacuum leaks in his 300 ZX twin-turbo. It is made of PVC, and you insert it into the infeed tube before the turbo (in place of the MAF). It has an air hose on it (like from a compression checking gauge). With the car off, you plug in the hose from your air compressor, and set your regulator on about 3-5 psi, and listen for leaks. The only thing we can hear is the EGR valve around the diaphram. And if you pull up on the diaphram, it makes its way thru the exhaust.

My old rule-of-thumb for checking EGR valves was to:
- Remove vacuum hose.
- Pull up on diaphram.
- Cover vacuum outlet with tip of finger.
- Release diaphram.
- If diaphram stay put, and only travels back after you release your from the vacuum outlet, the EGR Valve is good.....right?

Is the "missing" feel due to a bad valve?

What else can be my problem?

Cottom "Street 93" chip, 42.5lb injectors, TE-44, 3" Poston DP, 40 psi (vac unplugged).
 

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probably not...get your scantool so we can have some info to look at... :)

also a fp gauge that can be seen from the drivers seat
 

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If you're going to pressurize the MAF pipe to look for leaks, you should take off the rocker shafts so all the valves will be closed. And if you're going to pressureize it, go ahead and give it more than 5 punds. We run triple that in real life :)

The way I check a EGR is to stick my finger under the diaphram and lift up on it while the engine is idling. If it suddenly starts idleing like crap and goes back to normal when you let go of it, that's a pass. (doesn't mean that it's sealed up against the manifold compleatly though)

As far as jerking at 2K, is this in top gear with the torque converted locked? If so, get back up to 60 and just barely cover the brake pedal to unlock it. If the problem goes away it's the TCC circuit.
 
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