Can some of you knowledgable crossfire techs help me understand/tune my system? It runs fairly well right now but it has a few problems that I'd like to cure. So here's the deal. I bought this beast and the guy had no idea what had been done to it. He thought it was stock, as did I until further investigation. It no longer has the crossfire intake ducting to the hood. Instead it has a pair of modified carb air filters that sit of top. It draws air through my hood scoop where there's a large square hole underneath. The valve covers are not stock as they do not have an oil fill at all.. (do you know how hard it is to put 5 qts of oil in through the air breather?) I'm thinking it may have roller rockers but I haven't taken the time to check yet. The intake manifold has been off before Bc it has fairly new bolts holding it down. The EGR solenoid is gone. Wires have been snipped. Air pump is gone (I removed it when it locked up). Shorter belt in place. It had a 160F thermostat which I replaced with a 180 because I didn't like how high it idled. It now idles at 700 or so RPMs and here's my number one problem. When in neutral or park it idles smoothish at 800. When in drive it will drop to 600 and vary from 5-700 but it shakes at low RPMs and dies half the time if I don't give it gas. How do I fix this? Thanks

 

Congrats on your new ride and welcome to the forum.

It may need a tune up, (plugs, cap, rotor, wires, filters, pcv valve).
Or, it could be a vacuum leak. Check all of the vacuum lines for cracks or a loose fit.

I also have an 84. Great cars. Hope you find the problem soon.

Post a pic of it, too. (We love pics)

 

I'd start by putting the EGR valve back on. Sounds eerily similar to something that was happening to my '84. Short money, quick fix...

 

By visual observation, the wires look very new which leads me to believe the rotor and caps have been tuned up as well. I'd like to get some new plugs but they appear to be fine as well. Now on the vacuum.... This very well could be the problem. I've been fixing vacuum lines like crazy. The purge solenoid, cruise and EGR weren't hooked up when I bought it and the HVAC didn't work. Now here's some things I did that very well could be the problem. I reconnected the purge solenoid to the canister and PCV, because EGR solenoids are no longer produced for the 84 vette, I hooked the EGR valve straight to a venturi vacuum, the cruise is hooked to a throttle body vacuum, HVAC is repaired and connected to an intake manifold vacuum, and MAP is hooked to throttle body vacuum, and air diverter solenoid is removed and source is capped. I removed the IACs and cleaned them and the passages with carb cleaner which helped some. I'm thinking they could be out of sync...

P.S. Pics will have to wait until I can get the cover off of it. It's buried in snow Oklahoma got hammered with a blizzard.