Misfire in 1st and 2nd

[donsrno1]

I've got a bit of a problem with the hybrid at the moment and thought I would see if anyone else has had the same problem. Basically I'm finding that through 1st and second gear up to about 3k rpm under gentle acceleration the car is misfiring and very jumpy.

In 3rd gear upwards its fine at low revs and doesn't cause a problem but pulling off in first or going through 2nd is very jumpy.

I'm going to have a look later on to try and work out what the problem is but has anyone else had the same and if so what was the cause?

[donsrno1]

I should also say that it isn't so bad once warmed up, its still there a bit but not as bad as it is when the engine is cold.

[donsrno1]

Ok, I had a bit more time to pay attention to what was going on on my way home from uni and I'm thinking it might be the TPS. My reasoning is as follows, at first I thought it was a misfire but actually I think its like you are coming on and off the throttle very slightly which makes it very jumpy in 1st and 2nd but not very jumpy in higher gears but if you pay really close attention then it is slightly noticable in 3rd as well. If you raise the revs to about 1500rpm and hold the throttle constant then it will stay at that till the clutch starts to bite and at that point the revs raise suddenly to about 3000rpm.

Another thing though is that if you rev it in neutral then it revs smoothly and as if there is nothing wrong???

How exactly does the TPS work, does it basically measure how much the throttle has been applied and tell the ECU so that it know how much fuel to put in?

[Lunner]

do a search for it and check the resistance readings over the 3 wires

[BRUN]

How exactly does the TPS work, does it basically measure how much the throttle has been applied and tell the ECU so that it know how much fuel to put in?

yup, the resistance changes as the throttle opens

[donsrno1]

I was totally wrong on the TPS but in the end it turned out to be a really strange one that you couldn't really predict. On the idle control valve we noticed that it was missing a jubilee clip at one end but that didn't seem to effect it too much but we also noticed that the revs only went up in forward gears and it was perfect in reverse and neutral.

It turns out that the ICV was rubbing on the bonnet and when I engaged the clutch it was pushing up against the bonnet due to the engine rotating a little backwards, causing a vacuum leak resulting in the revs shooting up. Then in reverse the engine was pitching the other way meaning that it wasn't rubbing on the bonnet. Really glad to have figured it out though as there were a few of us having a look at it we weren't too sure what it was for a while. We only worked it out because we could hear a hissing like a vacum leak when engaging the clutch but when we opend the bonnet and tried to edge forward to see where it came from it didn't happen. Hopefully this will also explain my dodgy idle as the car has always idled abotu 1300rpm but I never got round to having a look at it so I'm thinking its always had an ever so slight vacum leak.

[donsrno1]

I was slightly wrong again actually, instead of the ICV hitting the bonnet and causing a vacum leak by pushing down on the pipe it turns out that the live feed wire to the ICV has snapped but it was still in contact sometimes but when the ICV connector hit the bonnet it was being disconnected so the revs were going shooting up.

The wire has broken right at the point where its crimped in the connector plug - is there any way of getting that out and re-crimping it or will I have to get a new connector?