I've been wrestling with a 3000rpm problem and glowing manifolds now for a month. I've checked for cracked vacuum hoses and checked the EGR tube. It looks fine. However, I noticed that there WAS no vacuum going to the EGR so I traced the hose and it wound up at the item you see pictured below. Let me explain.
The tube running to the EGR was plugged into hose #1. I didn't trace hose #2 to see where it went. Hose #3 is plugged off with some electrical tape from the previous owner. Hose #4 and #5 weren't connected to anything at all. When I disconnect everything from this regulator, the car didn't stall, stumble or anything. In fact it was as though I hadn't done a thing to it. Could this be my vacuum problem? If so, does anyone have a diagram or know where hose #'s 3, 4, and 5 are supposed to go??
This is on a 2.8 stock V6 Fiero, 85 GT model.

5 is the air inlet, should go to a line on the firewall and over to the air cleaner, doesnt hurt if it doesnt. 3 loops to 4. 4 is a pressure switch that closes when it has vacum, telling the ECM if there is vacum going to the switch

That assembly contains the EGR solenoid and the EGR sensor. You should have a vacuum diagram stuck to the bottom of the decklid...

Oh and I should add, thats not a vacum regulator, its the EGR control solenoid. Has next to nothing to do with driveability. The car will operate pretty much fine without the EGR, theres a lot of things it effects, but nothing you could notice by the seat of your pants. It should be reinstalled though. There should not be vacum to the EGR valve unless the ECM turns EGR on, which is usualy only at steady cruise. a 3k idle has got to be a heck of a vacum leak. Have you had the intake or TB off before this started? there is the IAC feed pipe that goes from the TB to the lower intake. It comes out of the TB and is easy to miss. This would give you a 1/2" vacum leak. Or second guess would be the EGR tube. If all else fails, plus all the lines to the valve covers, and take off the oil cap and feel for vacum. Sometimes the LIM gaskets can migrate up breaching the runners to the crankcase, then air gets sucked from the crankcase into the runners.

This should help.......

Diagram: buddycraig

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[This message has been edited by 2000RagTop (edited 12-26-2005).]

Here is a great thread by Buddycraigg that may help out a lot.

https://www.fiero.nl/forum/Forum2/HTML/045528.html

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May I make a suggestion, install a new egr solenoid and vacum lines to begin with, Re time your engine in the aldl *field service mode* to 10 degrees from TDC. Work on getting your idle down first. The manifolds are going to glow when you are sitting still and idling above or around 2000rpms no and if or butts on that one... With a 3000rpm idle, if the timing and above mentioned won`t fix it ==you have a larger vacum leak somewhere. EGR tube, brake booster, T.B tube that connects to lower intake, PCV connection at plentum , MAP lines. If you have had the top end off ,gaskets can bind on you also as 86GT3.4DOHC said. But start with the basics first, vacum gauges and alike can be gotten fairly cheap from places like habor frieght....Then work your way up....hope this helps some...

My timing seems fine though. One turn from the key and it fires right up