Running rough..low rpm only

[Pro3racer]

My friends car is running extremely rough in lower rpms. It feels like its missing and bogging at anything below 3000rpms..and at idle. Above 3000rpm, its fine. Any ideas? We did a boost test already, thats all good. I'm thinking maybe a coilpack?

 

[1gjosh]

getting any white smoke? when i blew my headgasket my car poured white smoke and bogged like hell until full boost. check for milky oil. and white smoke. repost and give more details/symptoms.

 

[abaum565]

Is the check engine light on? Mine had a bad (plugged) fuel filter and it stuttered when i took off but then was fine. Also maybe check the plugs and that they are gapped right, .28, and check the wires.

 

[ck1938]

My friends car is running extremely rough in lower rpms. It feels like its missing and bogging at anything below 3000rpms..and at idle. Above 3000rpm, its fine. Any ideas? We did a boost test already, thats all good. I'm thinking maybe a coilpack?

I had a similar problem last year and new plugs and wires took care of it.

 

[crankbender]

easiest check: Plug wires

Also check the water levels and look for smoke. The mitsu heads can puncture above the valves and leak water through the exhaust ports. At low RPMs it causes problems and at high RPMs you just blow it away. Vapor will be very evident.

Not fun I have had that happen to me.

Also you can have the plugs in wrong and still run!!!! check it if you have pulled any plug wires.

Make sure you didn't skip timing.

Check all the cylinders for firing and mixture (plugs and color...tons of pictures on the internet ifyou don't know how to look for lean or rich conditions based on spark plug color). If the car will idle pull the plug wires one at a time while the engine is running and see if a single cylinder doesn't cause a problem when you pull it. You will need to hold the wire so it still sparks to the head though to complete the wasted spark method ignition.