Hi everyone,

first of all, happy to join this forum! I bought a second-hand 2013 MK3 Focus 1.0 EcoBoost (74 kW) and since I owned it, it displayed a weird behavior. When starting it, sometimes the engine vibrates - a lot. If doesn't do it all the time, and when it happens, turning it off and on again will fix the issue. However, IF when first starting the car the engine vibrates, then the car would be very weird when accelerating; basically, when heavily pushing the gas pedal, as e.g. merging in in the motorway,  it stutters a lot, as if the car doesn't have power.

The issue disappeared after the last MOT (last summer) when I mentioned it to the mechanic and they replaced the spark plugs. However, it started doing this again lately: vibration when starting the car, restarting it fixes the vibration, but then the car stutters on acceleration. Again, it does not happen all the time, but when it happens is quite scary, as there are situations in which... you just NEED the car not to hesitate.

Any suggestions? I looked the issue up on the Internet and in this forum and I fount countless possible explanations for the stuttering/hesitation on acceleration, but vibration on engine start up seems unique to my car.

Hello Marco, what country are you in ?

You first need to get FORScan and check for any DTC's You may have a misfire caused by a faulty coil pack but you need to get information first

Also since the car is a 2013 then in less than 12 months it's going to need the wetbelts replaced which costs between £1200 to £1500.

I live in the UK. I don't have FORScan but it might be worth getting it. However I have to say that I've never seen an engine light/error message on the dash, and I guess that faulty coils should trigger an engine light?

Good thinking about the wet belt replacement. If this turns out to be expensive it might be worth buying a new car altogether.

Hi Marco, not all faults that register a DTC cause the Engine management light to come on, in fact I would say there are more DTC's that don't turn the light on than do.

FORScan is free for the standard version which does most things. You will need either a good ELM327 lead or the new vLinker FS lead to connect to the OBDII port.

FORScan: https://forscan.org/download.html

ELM327 lead: https://tunnelrat-electronics.fwscart.com/USB_Modified_with_switch_ELM327/p4541936_17045457.aspx

vLinker FS lead: https://www.bmdiag.co.uk/forscan-diagnostic-cable-for-ford-vgate-vlinker-fs

If the problem is an intermittent misfire then it will only trigger a fault code when a threshold number of them has been reached.

If you do get set up with FORScan then have a look in Mode 6 Tests, there should be Misfire Counters there for individual Cylinders.

There may also be PID's for Misfires under the PCM and you can monitor them whilst driving, not very convenient with the Laptop version of FORScan, easier with the paid for phone version but you do need a proper wireless lead for that version.