I have a 2000 blazer it has had new plugs wires cap and rotor put on. It won't start when it is really cold it turns over but won't fire then the battery dies right away, so I know it needs a new battery. but when the weather warms up it runs really rough you can watch the tach move, it spits and sputters when you go to take off and on the highway runs really rough, engine is either struggling to get gas or it is getting too much ??? It will actually downshift to a lower gear on the highway so it revs around 2500 rpms when it runs good it revs around 2000rmps that is doing 110 km/hr yesterday we hit +2 and it ran like crap. Any ideas as to what to fix next!! oh and it idles just fine
Any info will be greatly appreciated!!