Hi Guys

Hope someone can help.

I'm having a problem with my 1999 Octavia 1.8 20v SLXi. The problem first appeared a couple of months back when I'd nipped out to the post office, got there no problem. But when I got back to the car about 10 mins later she wouldn't start. It made the usual starting noise but wouldn't ignite. I kept trying to start her up every few mins and eventually she started about 25 mins later, so I drove home no problem.

I didn't experience any other problems with the car until last thursday when she cut out on me when I came to a stop at traffic on a dual carriageway. She wouldn't start again so I had to ring for roadside assistance. It took an hour for the pick up truck to get to me, during that time I had been trying to start her up every 10 mins or so but to no avail. The truck took me round the corner to a garage, I handed the keys to the mechanic and the car started for him on his first attempt. I felt like a right chump. I explained what happened and he told me it could be down to the immobiliser chip in my key, and that I should swap my key for my spare one (I knew this wasn't the problem, the immobiliser light would have lit up wouldn't it?). Anyway I drove the car home and swapped the keys over and it started fine. I didn't drive it for the rest of the day.

The day after on Friday 3rd August I took her in for a (coincidental!) 10k service at my local skoda dealer and explained what had been happening. They performed a diagnostic and found a few errors, the main ones being with the 'engine speed sensor' and another one to do with 'oil mix ratio' or something like that. They didn't fix anything though because I would have had to book it in again. I drove the car home and it seemed ok. However, when I got back in it at home to drive a couple of miles, I got just over a mile away and turned into a side road in third gear (should have been secondI know!), the rev counter went right down and the engine wouln't respond to me pressing the accelerator, and the oil pressure light started flashing and beeping (three times) at me. After 5 seconds everything returned to normal and I was able to continue driving. The engine did not cut out.

The car seemed fine all day saturday, although I didn't really do much travelling in it at all.

Then on sunday, I drove to the shops in the evening about a mile away. I was 3 mins in the shop and I got back in the car to drive back home and the car wouldn't start, in a similar situation to the first time this occurred a couple of months back. I kept trying to start the engine every 10 mins, until 40 mins later she finally started again. So I was able to drive home.

On monday (yesterday) I managed to drive 12 miles to work at 8am with no problems. The car started fine when I got back in it at 5pm too, however around 3 miles into my journey home as I was slowing down due to traffic, the rev counter went right down again and the oil pressure light flashed and beeped at me (three times again), only THIS time the engine cut out on me at the same time. The car was still rolling down hill so I managed to wrestle the car into an Aldi car park a few yards down the road (the power steering had been disabled obviously) and into a free space. I tried to start the engine again but it wouldn't start. Like before, it made the usual noise but wouldn't ignite. I rang for roadside assistance again and they came 50 mins later. During that time I managed to get the car started again after 40 mins, but I stayed put and played around with the idle with gentle revs to try and replicate the fault again. Sure enough the engine cut out again after around 5 mins of me doing this and wouldn't start again until I got the car home on the back of the rescue truck.

The car has not moved since, but I am able to cold start the engine no problem.

So, any ideas? It's going to a garage tomorrow morning but I'd like a few ideas to suggest to the mechanic, seein as I don't want to be spending a fortune for unnecessary parts and labour!

Cheers.

Power supply relay for the engine ECU?, under the bonnet there is a plastic housing which contains 2 relays I think it is the grey one, though there may be 2 grey ones.

I had same problems last year turned out to be a relay 109. Its housed in the dashboard fuse box on mine.Put relay 109 into a web search amd it will return a number of posts explaining the problem and symptoms. I picked a replacement up from a Seat dealer cost

I believe that the problem with relay 109 is specific to diesel engines rather than petrol.

Here's the fault codes that the service diagnostic brought up -

00561 - Mixture adaptation - Value above upper adaptation limit (mul)

16706/P0322 - Engine speed sensor G28 - no signal/empty/sporadic fault

Hopefully this should shed some light on the sit.

Looks like the engine speed sensor, here.

16706/P0322/000802 - Ross-Tech Wiki

The other fault here, it may be unrelated

00561 - Ross-Tech Wiki

Problem has been fixed (I hope anyway!).

It turned out to be the crankshaft position sensor. The car is running quite sluggish though, especially in 2nd and 3rd gear. Would that be the throttle body by any chance?