I noticed that when i am stopped at a red light my car's rpm is in the middle of .5 and 1. I have had my spark plugs changed, and oxygen sensor changed as well. (After getting those items fixed my check engine light went off.) If i am not pressing on the gas pedal hard my car will jerk at 18-20 mph. Is this normal?
My car has 197000 miles.
My car has an automatic transmission.
What you’re describing is not a normal situation. Although changing the spark plugs and O2 sensor tend to fix this type of issue, it could also be caused by dirty fuel filter, clogged fuel injector lines, or another electrical gremlin. It also may be the idle control system that is faulty. The best thing to do is have a local ASE certified technician, such as one from YourMechanic, complete a computer diagnostic test which will display an error code and point them in the right direction to fix the problem you’re experiencing.