Hi, I have a 07 1.8 duratec focus with 55,000 on the clock. It's had these very annoying faults for ages and it's driving me crazy.

When accelerating full throttle the acceleration is quite poor but if you accelerate with about 90% throttle it accelerates faster.

On the motorways as well it judders slightly when accelerating like it's holding back.

I have replaced both o2 sensors, map sensor, coil packs. I've cleaned the throttle body as well but none of these had helped. I also run it on 99Ron as it will pink on normal petrol.

It's does burn oil, but wouldn't of thought it would cause these issues.

Any help would be very much appreciated as I'm on the verge of selling.

Without live data you're throwing money away replacing parts it could be as simple as a throttle position sensor it could be the air filter is clogged or the fuel filter needs replaced incorrect plug gaps etc etc

The o2 sensors were for a different fault and the coil packs where second hand so not much money wasted. The spark plugs are New with the correct ngk ones. Fuel filter is in the tank.

Things I have noticed on live data is the short term fuel ratio goes to +15 when at full throttle. Also the throttle position when on the motorway jumps from 40% to 80% and the buffering happens, maybe to much air not enough fuel hence the high short term fuel ratio?

Juddering*

With engine off but ignition on the throttle position reads correctly with throttle input.

The ngk plugs come gapped at 1.3mm at least 10years ago ford changed it to 1.0mm as the old setting caused running idling and coil issues so its a free way of trying something even though the filters in the tank its not unheard of to find ones a bit clogged I'm no expert on the tps so I couldn't say if that's normal or not but I can tell you that similar issues have been caused by so many things its a nightmare to pin it down without fords equipment ......temperature sensors throttle bodies failing cat converters faulty injectors spark plug gaps tps sensors maf sensors a collapsed or split hose all of the above can cause the issue if you know anywhere that has live data diagnostics they can run it and see what the fuel system and sensors are doing to find the fault otherwise you're looking for a needle in a haystack

Thanks, I'll gap them to 1.0 and see if that helps.

Its worth a try as is checking the hoses for any splits I've been there myself with the old 1.8 lump and it was frustrating in the end I had it put in at ford on live data and they found the maf was giving erratic readings and a sensor was dead ide literally done the same as you scratching my head as to what it could be........do you do short journeys could it maybe need a good run and an Italian tuneup lol

I do a lot of short journeys but its does get driven hard from time to time. I regapped the plugs to 1.0 and the car does definetly feel better, but yet to test on the motorway so cant be sure its cured it.

The spark plugs however didn't look to great. Here's a picture.

I'd change those plugs, they've had it. No wonder it is running like crap!

Sent from my Gen 1 WAP phone

Those plugs aren't even a year old and probably haven't even covered 5000 miles!

http://www.ngk.com.au/spark-plugs/technical-information/spark-plug-analysis

Sent from my Gen 1 WAP phone

I'm pretty sure the spark plugs are like that because of its burning oil.

I'm going to try some marvel mystery oil down the spark plug holes and leave to soak over night. Then replace the spark plugs and change the oil and filter, and fill with 5w40 instead.