I have a 2004 Honda Accord 4 door. A couple of months ago it was necessary to accelerate very hard to avoid/get around an accident. Since then the car has idled very rough and uneven and is especially rough when the air conditioning is on. I had it serviced and the mechanic did not know what caused the change and said he could not do any adjusting since it’s computer controlled. The car seems to otherwise perform normally. Any suggestions as to what may have happened and how this can be corrected/brought back to normal?
Get another mechanic. There should be a check engine light on. It’s past time for some routine, scheduled maintenance. You can see the schedule in the Owner’s Handbook. Your mechanic can see the schedule in the repair manual. The fuel filter, air filter,spark plugs, pcv valve are past due. These items, in particular, can cause misfire, and loss of performance. There are more. They are in the BOOK.
You should be able to accelerate hard, or even very hard, every day without damaging anything or affecting the idle. If the mechanic you talked to can’t do anything, find another mechanic. An Accord should idle smoothly, no matter how hard you accelerate.
I’d be looking for a vacuum leak. Is the check engine light on?
I agree you should see a new mechanic. The car should idle fine.
I’m wracking my little brain to try to think of things that might have been affected by that sort of action that would manifest themselves as a very rough idle. The only things I can think of are a slipped timing belt or perhaps a failed motor mount. Both would have had to have been ready to happen anyway. How many miles does the car have on it? Was the timing belt overdue?
Note that these are simply wild ideas, not diagnosis. A good shop needs to look at it.