I have, besides pipes, a stock 89 gxl. This car refuses to idle. It starts up fine cold start reving around 3000 and starts fine hot but soon as I fire her up I have to catch it with the pedal. It will sputter and back fire anything under 2500rpm. I am alomst sure I have the vacume line routed right except the thermo valve with the three ports. The port closest to the intake has a check valve then a tee going to the cruise control and the lower intake. The second port is hooked to the bottom of the bac valve then the top of the bac is going to the underside of the upper intake also with a check valve. I can't figgure out what goes to the third port. The only help Im able to find is the dealer which has to be last resort. The car stinks when shes running burns the eyes a bit. I replaced the spark plugs, changed oil, checked the spark plug wires making sure they are right, and had all the injectors refurbished. Sorry if im hard to follow.

 

I will try anything at this point

 

does anyone maybe know of a understandable vacume line diagram for the upper intake? Thanks

 

I sympathize with ya. The FSM vac hose diagram is spaghetti. I'll have a look at my 90 NA when I get a chance. I do know that I don't have the cc routed to those lines.