89 GT stumbles 2500 and above

Bree said:

Good to hear the TPS was a big help.
Something else I'd check that is often overlooked is a little something called the MAP sensor. Manifold Absolute Pressure. Should be high on the firewall, just passenger's side of center, a black box about 1 1/2in wide, and 3in tall. Should have a couple wires and a vacuum line coming out the bottom of it. May not be it, but it's worth a look anyway.
Couldn't hurt to take the EGR valve off and clean it out real good with carb and choke cleaner.

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7991LXnSHO said:

I had 39-40 psi in mind with the line disconnected blocked, and varying with the line hooked up at idle. 10-12 extra psi sure will not help it run right. The aftermarket regulator I have is adjustable through the vac port. I think the stock ones are, too, but it’s been a long time since I had a stock one.

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