97 Chevy Suburban

I have a 97 Chevy Suburban, 1500. I originally came from Canada. The problem with it is (and no one can tell me how to fix it) is that when the temperature outside gets above 90, the vehicle misses, especially at lower RPM's when slowly accelerating. It will also miss much more when in reverse. The plugs are good, wires are good, rotar is good, the injection valves are good, but it continues to do this. When the temp is cold the vehicle runs great. Anyone with any ideas? Please.

If this unit has a throttle body fuel system check for an intake manifold leak near the cylinder that is missing. Lean mixture at low speeds, richer at higher RPMs.

Those motors are prone to intake gasket failures, but the motor is actually SFI, the type that has all the injectors inside of the upper plastic plenum on the engine. You could have possibly a leaking injector(not uncommon). Do you have a check engine light coming on? Usually a engine misfire will be recorded in the computer and store codes. Have your codes read. Something else would be to purchase a EGR gasket, and then remove your EGR valve and clean it thoroughly with a pick of some sort. Get all the carbon out of it. The Exhaust Gas Recirculation valve can be the cause of your miss. Other than that, the distributor cap and rotor are notorious for burning up contact points when the miles start to add up. How many miles do you have? Hope this helps -Chris