98 dodge stratus enginelight came on and rpm spikes n jerks

took it in to the mechanic they said it was just the gas cap but it happened again idk what to do

 

gas cap has NOTHING to do with driving problems.

what you should do is take it to a better mechanic.

 

but i trust this mechanic

 

I think you have a blown sensor. Take it to a real mechanic and tell them the issue and you think it might be a sensor messing with the idle. (I am assuming it happens only in 1st and 2nd gear and low speeds)

 

I have that problem right now and the code for it was P0132 high voltage bank one. It turned out to be the 02 sensor the dodge has 3 sensors this one is the by the fuel injection. Check your gas you are probably using alot of it.