Hi I have a 1995 Chevrolet Suburban with 201k on it. I posted on here before a problem with my rpms surging. I found the fix or so I thout by replacing the throttle position sensor. Now it is doing it again and a friend who is a "beginner" mechanic said to look into the map sensor. What are symptoms of this going bad and how hard to replace? At low rpms it will randomly drop to almost stall like it is starving for gas then surges back up and is normal then goes and does it again. If I really stomp on it it will run fine but lower engine speed it doesnt run right. I'm constantly thinking I'm gonna stall out at a red light so I stopped driving it. We just got our first real snowfall today and I need it again.

 

To me it sounds like fuel pressure! Check ur presure regulater!
And have u changed your fuel filter?

 

I have changed fuel filter just recently actually.

 

I would check the IAC or Idle Air Control valve, it controls the idle at well idle conditions like at a stop...
Might also want to check for any vacuum leaks...