Hello, First post on this forum,

I tried searching but did not really find what I was looking for.

I have a 99 Civic LX 4cyl. Auto Trans.

Car has 95,000 miles on it. No issues until today.

This car has been stored in my garage for the last 4-5 months.
Everything ran fine until today.

I went out to start it to make sure the battery was not dead, Started up without issue. and idled fine for approx 10 mins.

Then the engine started reving up and down. Betweeen 1k and 2k RPMs.

When I put the car in drive it leveled out at 1k just fine. Same in Reverse. (when there was a load on the engine) Back in park or neutral and it would start reving again.

I turned the A/C on and it would level out. Turn it off and it would start revving.

Then the check engine light came on. I turned the car off at this point.

I popped the hood and looked in the air cleaner to see if may a mouse had gotten in there. nothing all clear.

It doesnt have a plate on it right now, so I cant take it down to see what code it may have thrown.

Any ideas. Im thinking maybe a sensor is plugged or something with the intake? Plugged fuel filter?

Thank you in advance.