rough engine at low revs

shepv8 · 05-12-2011, 08:18 PM

Hi all,
our 06 focus LX has had an issue for about 4 years. its got 130,000kms on it. I noticed early on when we bought it that it was a bit doughy at low revs, like it needed a bit more revs than it should to get off the line with smoothness. In fact often when taking off slowly it would often shudder and rattle till it got going. I thought it was just a trait of the engine. Any way it seemed to get worse so I decided to pull the intake pipe off and give it a burst of sensor safe throttle body cleaner all around in there ( I did notice what appeared to be maybe oil pooled in the bottom of the intake manifold) I then changed out the plugs for new ones and when taking them out I noticed 1 had a cracked insulator, and another also had a smaller crack. Changed plugs and it went like a dream, problem solved....or so I thought. 4 or 5 months later problem returned and when I changed the plugs I found another cracked insulator. Changed this and all fixed again until 4 or 5 months when, same problem again. Ive also notice that under hard acceleration, especially in 2nd gear it has a miss/hesitation at around 2000/3000rpm ( not sure exactly where as its random but it does seem to happen more frequently when turning like going around a roundabout) Ive plugged in an OBD2 reader and its not got any fault codes stored.
Any ideas???

Russ · 05-12-2011, 08:54 PM

You might need to give few more details on the car mate, manual or auto ? Is the servicing up to date ? Timing belt and tensioner been done ? From what I have read the cracking is caused mainly by incorrect spark plug gap but can also be caused by using poor quality fuel, what type of fuel are you running the car on ? I would suggest a minimum of 95Ron in these engines although they are supposed to be able to be run on E10 but I don't trust the content of ethanol based fuels over here and still feel that 95RON or higher is a safer option.

shepv8 · 05-12-2011, 09:49 PM

Quote:

Originally Posted by Russ

You might need to give few more details on the car mate, manual or auto ? Is the servicing up to date ? Timing belt and tensioner been done ? From what I have read the cracking is caused mainly by incorrect spark plug gap but can also be caused by using poor quality fuel, what type of fuel are you running the car on ? I would suggest a minimum of 95Ron in these engines although they are supposed to be able to be run on E10 but I don't trust the content of ethanol based fuels over here and still feel that 95RON or higher is a safer option.

Weve owned it since new. Its a 5 speed manual. Servicing always done. Only 130, 000kms so no timing belt yet and the problem started , Id say about the 50,000kms mark . Almost always had 98ron premium with occasionally 95ron. Never had ethanol or 91 regular ulp. Always use shell or caltex, never cheap fuel. Only fault its ever had was the inlet manifold runner actuator replaced, but that threw up fault codes all the time and has been replaced without fault.

DeKa · 06-12-2011, 09:58 AM

Quote:

Originally Posted by Russ

Timing belt and tensioner been done ?

There's no timing belt in Duratec HE engines. It has a timing chain (thankfully!)

Russ · 06-12-2011, 10:48 AM

Quote:

Originally Posted by DeKa

There's no timing belt in Duratec HE engines. It has a timing chain (thankfully!)

That's right, I forgot about that, I discovered the site in the link a few months ago - I remember thinking to myself what a bonus it was not to have the expense of a timing belt replacement

http://duratec.wikispaces.com/