map question after switching renix to ho block and head

with my map plugged in my motor won't rev. It idles ok but a little ruff. When i add throttle it get's more ruff and backfires. With the map unplugged it idles better and will rev. I don't have much power but it still allowed me to drive it home at freeway speeds. At freeway speeds with map unplugged if i gave it too much throttle it would loose power and wan't to die. I would have to be very touchy with thottle to keep it at proper rpm to maintain highway speed. i attached renix manifolds to ho head and block. I had to grind dowles in intake to match it up. i also took a dremel to the intake ports in the head to raise them up a little so they would match the injector ports on the renix manifold. i used a renix gasket and ground it with a dremel to match. It looked like it lined up good when i bolted it on but with it running it sounds like there's a leak between the manifolds and head. Would this cause the map to behave irradic? Or do i have a bad map. With the engine off the ohms are within spec. I haven't taken a voltometer to the map yet with the engine on.

Test the MAP and spray around the intake manifold to check for leaks.It's better to leave the Renix intake gasket alone and grind down the outside edges of the intake manifold where it touches the exhaust manifold in order to get it to fit.

If you leave the MAP disconnected and it runs better, you've got a HUGE vacuum leak. Without a vacuum signal or with a disconnected MAP plug, the ECU assumes the engine is under extreme load and richens the mixture. This is compensating for the excess air entering the system through the vacuum leak (which is probably at the intake gasket) and allowing the engine to run better (all-be-it still not correctly)

I'd recheck for the vacuum leak and see if it's at the intake.

cruiser54 said:

Test the MAP and spray around the intake manifold to check for leaks.It's better to leave the Renix intake gasket alone and grind down the outside edges of the intake manifold where it touches the exhaust manifold in order to get it to fit.

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spray what exactly? it sounds like you did this swap. any pics of what you ground down to make it work?