For some background: My car idles fine. Cold start, no problem. But for the past 9 months or so, every once in awhile, the car really struggles on a warm start. Shaking, rough idle, needs gas. Then after 30-45 seconds it runs just fine.
Yesterday, a check engine light finally came on (along with VSA/TCS lights). Checked the codes: Cylinders 2, 4, and 5 misfire, along with P1399 - Random cylinder misfire. I adjusted the valves and changed spark plugs 2 years ago, tried Seafoam (gas, oil, intake) last month. I have a couple of questions before I work on this....
1. I'd like to check the coil packs first, preferably one at a time. Is there any problem with just replacing one? And are the aftermarket brands ok or is the general recommendation to go OEM only?
2. With the EGR port, I cleaned the port out on the underside of the intake manifold when I adjusted the valves, but left what was built up on the motor. What's the best way to clean this? And is it OK for this crud to fall into the engine? (if that's where it even leads to).
Not the same engine, but this is what I'm referring to:
![Click the image to open in full size.]()
Yesterday, a check engine light finally came on (along with VSA/TCS lights). Checked the codes: Cylinders 2, 4, and 5 misfire, along with P1399 - Random cylinder misfire. I adjusted the valves and changed spark plugs 2 years ago, tried Seafoam (gas, oil, intake) last month. I have a couple of questions before I work on this....
1. I'd like to check the coil packs first, preferably one at a time. Is there any problem with just replacing one? And are the aftermarket brands ok or is the general recommendation to go OEM only?
2. With the EGR port, I cleaned the port out on the underside of the intake manifold when I adjusted the valves, but left what was built up on the motor. What's the best way to clean this? And is it OK for this crud to fall into the engine? (if that's where it even leads to).
Not the same engine, but this is what I'm referring to:
