i changed my spark plugs at 50k miles and the car currently has 67k miles (08 rdx). i started noticing recently that when i start the car, it has a very rough start and stutters when you start the car. when the car stutters for the second the lights on the dash go off and on before the car starts up.

is this due to battery, alternator, or some other problem? best way of diagnosis?

help much appreciated, thanks guys.

 

First thing is to check that the battery terminals are clean (no corrosion) and secure then go from there

 

There are a dozen issues that could cause this. Take the car to a qualified mechanic and have the issue properly diagnosed.

 

start with your sparkplug job.
look for disconnected sensors, might even have to go back in to see if the sparks plugs are all tightened down, if the gap didnt close, if you didnt put the coils/wires back right.

 

You only have 17000 miles on your new spark plugs, and assuming they are OEM replacement, and there are no defects with it, I would look at the injectors. Sometimes fouled injectors, and faulty ones, continues to drip a little gasoline after the car has been turned off. This can easily cause the early morning start-up engine vibrating. Run a bottle of the Chevron fuel system plus or concentrated injector cleaner, and see if it improves it. If not, just go over to Orielly's or Pep boys and have them run a quick alternator charging test. Don't assume it is the spark plugs just because the engine is vibrating.

 

+1. Definitely do this first.

If there was a problem with your sparkplug installation it's very unlikely that it would have taken 17000 miles to show up. Additionally, a sparkplug problem rough enough to shake the engine would light the MIL and send a mis-fire code. (Mis-fires are critical because of possible damage to the catalytic converter.)

If it continues after your terminals are clean and tight, take mav's advice. The battery/charging test is free. At 67k miles and 3 years, there's a possibility you need a new battery; the OEM batteries are weak.

 

I got 70000 miles. OEM spark plug at 50000 No problem at all with Red Top Battery.

 

You gotta love em Red Tops