'07 GP 1.4 8v - Intermittent problem when lifting foot off the gas, especially when going downhill. The car seems to jerk (a bit like trying to drive slowly in too high a gear) - it actually seems to shake backwards & forwards quite sharply, just for a second or two. Sometimes I just have to dip the clutch to stop it. It seems to happen more often from cold, but sometimes not at all.
I had the gear box mount replaced, which seemed to help, but I feel like it's a slight misfire, or ECU/software fault. There's no odd noises when it happens. I replaced the MAP sensor because of a cold start problem - it's not a Bosch one, just an eBay cheapie, but the jerkiness was there before I changed it. I have also changed the spark plugs & cleaned up the earth points.
Any ideas, please?

For a start, replace asap the cheap map sensor with a bosch original.

Seriously... throw it away!

Sounds like mine when engine and gearbox are cold. I thought its normal..

I have similar problem, I have also changed the gearbox mount but was wondering if the others needed changing

out of curiosity I checked my map sensor (as it had been replaced by previous the owner) and I found that it was covered in oil. I assume this oil has come from the crankcase blowby, should it be coating the sensor though?

samtyler said:

out of curiosity I checked my map sensor (as it had been replaced by previous the owner) and I found that it was covered in oil. I assume this oil has come from the crankcase blowby, should it be coating the sensor though?

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Yes it's normal don't worry.

Is it an original bosch ?

Ok cheers, yes it's a Bosch one

Check mountings.

Just to return to this, after some time, I finally got round to replacing the MAP sensor with a Bosch one, and, it's still jerky! Possibly not so bad as before, but it's hard to tell as it's so intermittent. Still more likely to happen when the engine is cold. But it always seems to be when going down a slope, where I'm lifting off the gas but not braking. Weird.
Anyone else had/cured this problem?