i noticed my car was revving high at idle most times about 1000rpm to 1500rpm sometimes it would settle and on tick over it would be ok then rev slightly higher again i had a mechanic have a look he cleaned the throttle bodies and the idle speed seemed ok until he test drove the car he noticed at 30mph in 4th gear the car didnt feel smooth and suggested the cold start valve might be at fault does this sound right and where is the valve? how much ? and is it easy to fit?

thanks in advance mark

Try cleaning the Throttle Position Sensor connections. Worked for me as I have had a similar problem a couple of times over the last few years.

Cheers, PaulN

 

Check your air filters they may be blocked, also after each clean or change of filter give the ecu a chance to re-learn the air intake before looking for faults.

 

Jeff

Doubt its the cold start valve - as he calls it What can happen is when the throttle bodies are cleaned, all the shit is washed to the back of the intake plenum where it clogs the idle valve... Looking from the front of the engine, the idle control valve is at the back on the right - you'll see a rubber hose bending round the back from the right hand side - this goes onto the valve...

 

Also Jeff is correct, the ecu should be reset when any work is carried out on the intake that will improve breathing. Do this by disconnecting the battery for half an hour. To be honest the battery should be disconnected before starting any work on cars anyway and cleaning the throttle bodies takes longer than half an hour.... if you catch my drift

 

Another possibility is a hose has been accidently knocked off - check under the boost hoses to see the small vac lines are still connected.

 

Yet another possibility is the connectors to the coilpacks, injectors, ptu or cas. Check these are secure and clean....

 

HTH

 

CheerZ,

 

Andy

Ooooops sorry forgot to say how to clean the idle valve....

 

Remove the rubber hose I described and spray carburetor cleaner in to the valve body - this should free up the slider...

 

CheerZ,

 

Andy