Hey guys here's my issue: When my Monte is idling the rpms fluctuate pretty badly. So much that the car jerks forward when the car is in drive. The computer is also throwing a lean code. I replaced the MAF about a year ago. Fuel Injectors maybe? Any input will be greatly appreciated.

 

My first guess would have been the MAF, but if you've replaced it, it can't be that lol.

Not sure what would cause such a fluctuation. I know my Monte fluctuates a little. How much does it change, RPM wise?

I'd probably start with new plugs, wires, clean the throttle body up, clean the MAF sensor, even if it's newer. Sometimes a dirty MAF can really mess things up.

 

If the engine is running lean I'd do a fuel pressure test - both at the schrader valve and the fuel filter. That way you can verify proper pressure being delivered from the pump and the regulator. Another quick test would be to pull the vacuum hose off the regulator and check for fuel. If fuel is present in the hose then the regulator is bad. If pressure is acceptable and the regulator is okay I'd check for a vacuum leak.