95 7.5 liter random issues, speedo, revs by self, abs, brake light
 

95 e350 automatic with 7.5l

Ok well at idle its smooth as hell, then after I start driving awhile, it will like just rev hard , punch it with out me doing it then back off, just does it randomly...

The speedo dances like 90 percent of the time to 0 to proper speed to all over the place? Whats loose or broke?

Abs light is almost always on and e brake light turns on and off in between me hitting bumps on the road, even tiny minor bumps...

How do I scan for codes? It's obd1 I believe

Any ideas guys?