Clean or replace your Positive Crank Ventilation (PCV) valve. It's the little black plastic elbow (3rd gen V6s) on the drivers side of the front tappet cover.

To check:

With the engine off:

Carefully pull the elbow out of the tappet cover. I just 'pops' out, but be gentle.

Turn on the engine (with car in Park or Neutral - put your handbrake on too!)

Standing at the SIDE of the car, with engine idling, place your finger over the end of the PCV valve. It should suck with good force. Try this several times to ensure a consistent result.

If it's not sucking, remove the PCV valve from the hose and feel for suction at the hose end. No suction here indicated a blocked hose. Replace and retest. Clean the PCV valve with carbi cleaner etc for good measure.

Check that the PCV valve opens when the head of a nail is pressed carefully and gently into the plunger of the valve.

I cleaned mine with carbi cleaner, carbi cleaner isn't always good for plastics so time will tell here :doubt: If you do use carbi cleaner, rinse with water straight away and dry thoroughly.

When the PCV valve has been cleaned (use the nail to carefully scrape crud off too) replace it in the hose and recheck suction. Should be good now. If not sorry, another post perhaps :(

Reinsert the PCV valve into the tappet cover. Enjoy.



P.S. Please post with whether this helped your idle or not. Cheers.

Can you show us a pic of the PVC or the "front tappet cover"??

As I have no idea, and I cannot picture it in my head....

err there are a number of things that affect idle problems, not just the pcv valve

err there are a number of things that affect idle problems, not just the pcv valve
Absolutely. But how many people here are running 10yr old cars with original PVC valves but change their oil, plugs, leads etc regularly.

This wasn't meant to be definative (I have the CD manual for that), just a helpful reminder :D

What is the PCV Valve supposed to do ???

TPS switch also, Mine was not sending/switching to the correct position, now its alot better.

What is the PCV Valve supposed to do ???
Because the rings on the pistons don't completely seal, air can be forced past the rings into the crankcase. If the crankcase becomes pressurised, the motor has to work harder to rotate and overcome the pressure on BOTH sides of the piston. Most felt at low rpm as the motor has less inertia to force against the crankcase pressure. That's why the motor is struggling at idle.
That's why GOOD rings are needed for forced induction motors.

The PCV allows this pressure to be vented from the crankcase and fed into cyclinder #1's intake to be consumed in the combustion cycle.

PCV = Positive Crank Ventilation.

So if the PCV valve is in trouble you will experience poor idle and reduced performance.

If you remove the ISC then you have to have it reset on a diagnostic machine at a Mitsubishi dealer.
Mine was playing up so I removed it and cleaned it out (it was filthy). It doesn't idle right so I've been told by Mitsubishi it has to be reset.

OK.

What other products could be used to clean the PCV?

Would just plain water and a towel do the trick?

Most of the crud actually scrapped away very easily with the butt of a nail that I was using to prod the valve. Warm dishwashing liquid solution and a clean rag will probably yield good results. Just be gentle and take your time.

Cool!

Cheers man!