My car is running like a real pile right now, and I need to figure out what to try first. It seems like only after it warms up that it starts to miss while idling or just cruising. It smells very rich. Then, when accelerating it cuts out at about 3500 RPMs and totally looses power. My opti only has about 30k miles on it, so hopefully that isnīt the problem. What should I try first, or how can I troubleshoot this? Itīs not throwing any codes. Would replacing the ignition module and coil be a good place to start? Iīm pretty sure these are both original with about 110k on them. Thanks for your help.

 

I have traced stumble issues back to the coil. Just the other day it was crapping out at 5.5K RPM, it was the coil. I have also seen coil wires cause problems.

I would replace the plugs, wires and coil to start. It wont cost much to rule those out. I am willing to bet your current plugs are fouled the way you are describing it. Make sure the new plugs are gapped correctly. Been there in the past.

Clean the MAF elements carefully with no residue electronic cleaner and a swab. Remove the throttle body, take it apart and clean it well.

Check all vacuum fittings for leaks. Check the EGR and make sure it is closing completely when it should.

That should get you started.

 

Thanks wrd1972. Iīll try a few of those things when I get back to the States, Iīm in Spain right now. It def isnīt the EGR, because it doesnīt have one anymore, and the wires were new when the opti was and they all look great. I think iīll start with the coil though.

 

If you blocked off the EGR make real sure there are no leaks around the plates including the plate on the right manifold. Leaks there will mess up the A/F mix.

 

I've had coil problems cause this but only above 4-5k. Check for arching at night. If its not arching around the coil like crazy at idle, its probably not the coil.

Just by the sounds of it, it sounds like your cat may have gone out and plugged up your exhaust. This will cause a tottal loss of power from 3000 up. While the car is idling, listen to the cat on the passenger side (not sure what year your car is) and if you hear a hollow rattly sound coming from it its definatly clogged.

Finally it could be a lack of fuel pressure causing the car to fall on its face at higher rpm. Hook a fuel pressure guage and tape it to the windshield then go WOT to see if it drops abnormally low once it gets to 3k rpm.

 

Iīm pretty certain thereīs not a leak around the EGR blockoff plate. It is possible that my cat is plugged, but it shouldnīt matter because itīs laying in a shed at my parents farm. I think Iīm going to order a coil and ICM now so itīs there by the time I get back home in a couple weeks. Itīs not just loosing power gradually in the upper 3kīs, itīs hitting a wall and refusing to rev any higher. Itīs missing at all other RPMs though too, but only after its warm.