Have an 02 Accord. 112 K miles. Has my mechanic put in new timing belt and water pump and spark plugs. Got it back and noticed rough idle. Took it back to him. He did notice rough idle. He said he had to run it for ten minutes for computer to do memory run and should solve problem. As a note car shifted funny from first to second gear (automatic), but after he did his memory deal this fixed that problem. The car originally had idle speed of 750. Now when started in goes to 100 for first 5 minutes of cold start then back down to 750 where it continues to idle rough in park, rev and drive. He also checked motor mounts and said all we good. Any suggestions?
Thanks,
Rob

A simple one would be to buy a can of Sea Foam. And run it through your system to clean the injectors and the inside of your engine. Also a can of good injector cleaner in the fuel tank. Follow the directions on the can and be prepared for lots of smoke when you first start it back up. Also if you didn't already change your fuel filter.

Is this a 4 cyl or V6? Does the car have good power or does it now LACK power? If it lacks power after his timing belt replacement, his valve timing may be off. If it's the 4 cylinder engine, the balance shaft alignment may be off. Also, he should have adjusted the valves when the timing belt was replaced. The exhaust valves tend to recess into the head, given enough time and the cylinder head will be damaged.

Is this a 4 cyl or V6 ?? Does the car have good power or does it now LACK power? If it lacks power after his timing belt replacement, his valve timing may be off. If its the 4 cylinder engine, the balance shaft alignment may be off. Also, he should have adjusted the valves when the timing belt was replaced. The exhaust valves tend to recess into the head, given enough time and the cylinder head will be damaged.

The car does not seem to lack power and it's a 4 cylinder. I'm not sure if he adjusted the valves when the belt was replaced. I will ask him. Would it be a good idea to just take it in to the Honda dealer? It's been about a week since I had it done. As a note, the RPM's seem to be at around 720 at idle. Thanks,
Rob

. Clean throttle plate, throttle body, and upper and lower ports.

. Clean Idle Air Control Valve (IACV):

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-7.html#post1054149

. Change PCV Valve.

. Clean air box and replace air filter.

. Set idle rpm to specification.

Start using full-synthetic engine oil (e.g. Mobil 1). Change oil and filter every 6,000 miles or 6 months, whichever comes first. Change transmission fluid every 30,000 miles, using Mobil 1 Synthetic Multi-Vehicle ATF.