Rickard1982

When was the last full service? Air filters oil? Etc etc

ian_6301

It may well be that the O2 sensor is indeed buggered, which may be throwing the mixture out. Primary controls mixture. Secondary checks the Cat is working.

Are the primary and secondary sensors the same part numbers? If so, try swapping them over and see if it drives properly. You'll still have a CEL, but you can solve that by popping a new lambda sensor in when you get a chance?

mrgrumpy

These are the symptoms I had when my o2 sensor was on it's way out.

johnbuck

Thanks for all your replies.

Checked and eliminated most suggestions, everything's clean and no perishing evident.

On my second tank fill up so fuel is definitely good.

Air filter & oil are new.

Did take the Map sensor off, all connections were clean and tight.

Just the IACV to take off and give a clean.

Not sure about the O2 sensor; it was a 1 off CEL and hasn't reappeared. If the sensor was faulty wouldn't it keep throwing off CEL's?

U9aXy6Dn

If the O2 sensor was faulty, yes, it would continually throw CELs - or at least, it would throw them enough to draw attention to it.

I wonder if it's related to the motion of the clutch. Mutually I've considered the alternator as well. There's also an earth on the gearbox casing.

It sounds as though the initial moving away process pivots something into an inoperable state, then once moving, it returns to normal and a proper connection is made.

mrgrumpy

I never had a cel when I had my problem,got an auto electrician to sort it.

westburywheeler

Try a ecu reset, start up and leave to tick over until the rad fan cuts in twice, switch off and leave for a couple of minutes and then restart.worked for me when spun on track and had cel light on, mine ran perfectly normal and went back on track, took 50mls for the cel light to go out and has been running good since, about 12mths. Good luck.

noodels

Would unplug re plug everything
vehicle speed sensor if there is one ??
dash cluster
ecu
thermostat earth or sender
ignition relay clicking as it should ?
is the ignition advancing
suction when fuel tank cap removed try without cap on ?
battery feeds/earths everywhere

unclefester

Also check the little O ring is under the MAP sensor and if it is there, that it's in decent condition. Actually, reading that first post again, i wonder if it's a combination of IACV and slow / dying 02 sensor and once the car has warmed up - it's no longer relying on it. Not dead enough to chuck a CEL but slow enough to make the car misbehave.

I would still take the IACV off and give it a clean out with WD40 and an old soft toothbrush though.

Guide here https://www.s2ki.com/s2000/topic/492...#entry10624891

johnbuck

Thanks, Map sensor o ring is still intact and perfectt condition. Going to have a go at the IACV today and if that doesn't cure it, replace the O2 sensor.
Car did it again yesterday.30 mile drive, parked up for about an hour so car was still warm, then went to drive away and same problem; let it sit and idle for a couple of minutes and then drove away perfectly.