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Surging and uneven revs after timing belt change


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Hi All,

I recently had my Mk3 Ti-VCT serviced by my usually decent indy along with a new timing belt, water pump and tensioner.

However, since getting the car back I noticed it felt really strange and not as smooth as it was prior. The only way I can describe it is when driving it, it feels like your driving over an uneven road all the time like it is surging when going along. It is also jerky when setting off from cold too, which it was not before.

I've also noticed the idle is slightly uneven and you can now feel the vibration from the engine. Another thing I noticed when holding the revs at say 2000rpm it surges slightly up and down rather than holding steady.

The mechanic has had it back in and found no faults, to him it felt normal. He did have one of his other guys have a look at it too and he did notice the surging. They've now replaced the HT leads and plugs.

Since doing all that they've returned the car to me as being 'fine'. But disappointingly the fault still seems to be there.

He said he has done diagnostics on it and no fault was returned; in addition he is adamant it is not the timing belt etc. as he said the engine would not run at all.

I usually trust my indy but this time I am feeling a little dejected and my gut is telling me it is the timing but it is ever so slightly off.

Does anyone have any idea what it could be?



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I have been getting this issue that started Saturday / Sunday, I have not had a service done or anything since I changed the battery and added a remap a couple of weeks ago (map has been removed just incase).

Today I hooked the car up for Forscan and it had some DTC codes relating to loss of communication to (I think) the Body Control Module which I clear and all started went back to normal. Later on I went out again and the problem returned, I was unable to hook the car back up again as had to get ready for my night shift at work so cant really look again till Friday.

I dont have the same engine as you though, I have the 1.0 (125) EcoBosst engine in a 2012 model.

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I'm not an expert on this but I think the Ti-VCT engines are particularly critical to set up when changing the timing belt because the cam variators have to be set up correctly. I wonder if your indy garage has the correct training and tools to do it properly. I would imagine that a slight timing error wouldn't be sufficient to trigger DTCs so your gut feeling may be correct.

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I'd definitely be getting a 2nd (professional) opinion, if it is the installation of the cambelt that's not right the 2nd opinion can do you a written report to go back to the 1st garage with.

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Yeah my gut would concur with yours. O don't know much about engines compared to others on here, but if garage insist camber is fine, leads and sparks are fine then irregular idle must be valve/cam timing. And they're probably right as cambelt would have caused problems or at least thrown a crank sensor light...

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Thanks guys.

I'm going to head on over to my local Ford dealer at the weekend and have a chat (or at least try to) with one of the service technicians to pick their brains.

It's really annoying considering you expect the mechanise you've trusted for nearly 5 years spins you a yarn, initially he said 'oh it'll take a while to settle down' until I demanded he look at it. Never had a cam belt require settling in before!!


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