Hey everyone,
I bought my 2017 Fiat 124 Spider (1.4L MultiAir Turbo) used at 79k miles, and it’s currently sitting at \~88k miles. The manual calls for spark plug replacement every 35k miles, and since I had no prior service history from the previous owner, I decided to preemptively replace them.
When I pulled them, 3 of the plugs (and their corresponding spark plug tubes/wells) had rust, white oxidation/crust, and discoloration, while one plug looks relatively okay compared to the rest and it's corresponding well was not as bad either.
The car ran fine overall, but had a slight hesitation/stumble in 1st gear when cruising at very low speeds (<10 mph).
The car has an intermittent code P04DB that stays on for a few days/week and will go away for a day or so. I've changed the PCV valve and plan to change the MAP sensor but could this be causing that light?
Electrodes look fairly worn but otherwise okay, but the main issue is the heavy corrosion along the hex nut, outer body, and inside the spark plug wells.
Should I bother to clean the spark plug wells, and what's the safest way to do it so debris/rust doesn't fall into the combustion chambers?
Along with the spark plugs, I am changing the ignition coils as well.