ancdmd

I've done quite a bit recently to make my car run well by making sure sensors are fresh and clean and working properly, such as the MAF, engine coolant temp sensor, knock sensors, oxygen sensors, and spark plugs. Car is an '02 with 179k miles. I had it running well after replacing both upstream O2 sensors, which eliminated a persistent pinging under throttle. However, recently the engine had started to ping a lot again, especially under throttle. Idles just fine. New plugs made no difference. I'm wondering about the coil packs; all are original. Can these coil packs degrade over time, causing the engine to run poorly, without completely failing and throwing a code? I saw one guy on here replaced all 8 packs and restored power and smoothness to his old motor. But at $500+ for parts, it's a lot to just throw at the car without knowing for sure they'll make a difference.

SH212

While the car is on and warmed up, disconnect each coil pack 1 by 1.If no change in idle when disconnected then thats your coil.

mrboca

Agree, $500+ is a lot of money to spend, then you find out you have a vacuum leak or dirty fuel injectors, dirty fuel filter or something else

I would start with the low hanging fruits first. You had pinging, you replaced O2 sensors. It solved the pinging problem, then you had pinging again. I think the O2 sensors were not the cause, but the symptom. You change the ignition coils, it may or may not solve the problem.

I would get a a scan tool that is capable of showing live data for fuel trims, O2 sensor performance, MAF output, Intake / coolant temperature (as seen by the ECU), pending codes, mode$06 tests, etc, so I could see what is going on better.

1A1

Check your coil pack connectors. They get brittle with age.

Steve