Vehicle will accelerate and decelerate on its own and high fuel consumption

Hello,

To enable us to assist you further please have the vehicle scanned for any possible fault codes which could help us diagnose the problem.

How to scan.
https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Once scanned please post any fault codes here so that we can assist further.

Please let us know how you get along.

Cheers, Boris

P2646
P1078

Hi, I'm Dan.

The first Code P2646 has to do with the VTEC system being stuck off. The leading cause of this failure is the engine oil level being low or dirty. The first step is to clear the code, change the oil and drive it to see if it returns.

The second one is the P1078. This usually points to the little motor that activates the intake flapper doors on the intake manifold. I've attached the diagnosis procedure for that below. You need to remove the motor, see if the intake flaps move freely, and also see if the motor moves.