power surging

[robp]

I've just started havign a problem this morning, car is fine in 1st and 2nd, but in 3rd i am having trouble, get up to about 3k, and the power seems to flitter a bit, then get upto about 5.5k and it seems to loose all accelleration for a few seconds (probably less) and then it picks up again and is fine up to 7k.
not tried 4th or 5th yet as the traffic was too slow going this morning to get to those sorts of speeds. I suspect its an air intake problem as a friend has a similar problem with a lancia delta 1.6 turbo engine, but anyone else had similar? any advice? I dont want to replace the hose if i can help it as ideally i'd like some CF pipes from darren, and dont see the sense in paying for another pipe for the couple of hundred miles i am going to cover before the car goes into storage for the winter

[Nige]

Can't imagine it's the air intake hoses unless they're obviously damaged. Worth checking the air filter to see how dirty/clogged it is. However, sounds more likely to be the early stages of a CAS on the way out? Do you get an engine check light at all? As ever worth checking your base timing is set to 16 deg BTDC. Also suggest you whip the plugs out and have a look at them to confirm the gaps are correct and you have a clean burn on each cylinder.

[robp]

The car was only serviced 1000 miles a go at horizon, air filter is a nwe green totton filter that has covered about 600 miles, will get the plugs out later. I do get the oil light flickering on occasionally, but i do need to top it up soon.

[Nige]

Air filter should be ok then, just check to see it's still there and in one piece. Flicky oil light would concern me, what's the oil pressure reading like and does the flicky oil light relate to a low oil pressure reading. Also and not wishing to insult you but are you sure it's the oil light and not the CEL light (orange, RH end of row of lights, picture of an engine)? If it is this one then I'm still thinking CAS on the way out a paperclip test will confirm by flashing the fault code see here .http://lotuselancentral.com/repair/aldl.htm

[robp]

yep, definatly the oil light, its red and its got an oil can on it. and yes the oil pressure is low too - sub 5 at the moment. I've put that down to it wanting feeding again (slightly leaking sump gasket to be sorted very soon) Will check the filter when i get home later.
I've also noticed that the idle seems a little high (upto 1500) but had put that down to the car being very cold in the morning. does that sound likely?

Whats involved in sorting the CAS?

[Nige]

CAS details here http://lotuselancentral.com/repair/cas.htm

You no longer need to replace the whole part just the Hall effect sensor, these are on offer from Lotus at the moment details are here:
http://lotuselancentral.com/forum/viewtopic.php?t=2912

As far as oil pressure goes, just below 5 bar when running at some speed is normal, a little higher when cold. It usually drops to about 2 bar when warm and at idle such as sat in traffic.

The fast idle might steer fault diagnosis in another direction though possibly the Idle Air Control IAC.

Worth doing a paperclip test to see if you have any fault codes stored as it can be a useful short cut to identifying the problem.