If the check engine light has come on you need to read the code(s) that have been set in order to make repairs. Your local auto parts store can do this for you. If no check engine light has come on, it may be time for a complete tune up.
Have the motor mounts checked.
If it is running fine at high revs the most likely problem is an injector
It is best if you wait until you are sober to troubleshoot your engine. Stop smoking and give yourself time to sober up first.
Without much to go on, I would suggest you look for a vacuum leak, especially if the engine runs good under acceleration and only shakes and shudders at idle.
Going uphill puts an extra load on the engine. It might be time for a tune up.
What type sled?
one word dealership....
99 pontiac montana 1374 engine code
There are four causes of the engine failure. The four causes of the engine failure includes engine overheating, lubrication problems, misassembly , and detonation.
Take it to AutoZone, it's free.
With computer Diagnostic equipment and the ford shop manuals. This is not an engine to be worked on under a shade tree.
Get a shop with the appropriate software for your engine to hook it up and do a diagnostic on it.