Why is rpm fluctuate and car jumping while driving

Hi Tommy,

Is your check engine light on? Even if it isn't, your car's engine computer may have codes stored that will give you a clue about what's going on with it. You can get your codes scanned for free at most auto parts stores here in the US, or you can buy an inexpensive dongle that will plug into your car's OBD-II port and allow you to connect to an app on your phone that can read the codes. You can find dongles for under $5 online, and there are several free apps available that can connect to it; I personally use one called Torque.

In general, most issues bad enough to cause the kind of misfires and variations in RPMs that you're seeing will set a Diagnostic Trouble Code (DTC) pointing to which sensor is showing a problem. The codes start with the letter P followed by four numeric digits, such as P0301, for example, which would indicate a misfire on cylinder 1.

If you can get your car scanned for DTCs then come back and add that information to your question we'll be in a better position to try and help. As it is, your problem could be any number of things, including air, fuel or spark problems; there are too many possibilities for us to be able to guess without some troubleshooting, and the DTCs are the best way to start.