Hi..

My automatic Fabia is running really slowly, starts and idles ok, but upon driving it, it struggles to get to 40mph and after about a mile it drops to 10mph (5mph on a slight gradient) shifting gears doesn't help it any, I have to just put on the indicators and pull in to let cars pass safely. When not under load, the engine revs freely as before.

The throttle valve (removed, cleaned and tested) opens ok when you rev it. I pulled and cleaned the MAP sensor (14.5psi / 6.5psi) when I saw a P0106 on the scanner but it's gone now with no other codes showing.

Checked all vacuum pipes and can't find any leaks (brakes work ok).

Coil packs and plugs were replaced last year as was the exhaust and cat.

My scanner shows all the correct numbers and smooth operation of the TPS pedal when I display the graphs and voltages/pressures and temperature readings on live data mode.

The engine has 90k miles on it and has performed faultlessly for years, getting serviced once a year, but this problem happened without warning (no overheating or odd sounds) whilst driving about 65mph along a dual carriageway, suddenly, power was lost and without any engine warning lamps, we managed to limp it into a carpark.

I'm struggling to find out what this problem is, so if anyone has any suggestions, it'd be appreciated.

Tomorrow I'll fit a new coolant sensor and MAP sensor to see if that helps.

Does this engine have an EGR valve? Could that be the problem? If so where is it situated?

EGR would be just to the right of the green oil pressure switch if there was one.

Your car has not got one.

Have you searched for problems with automatic mk1 fabias in this forum? I think there have been a few discussions in the last few years.

Search using engine code (BKY?) and automatic as search terms, I suggest. Maybe using an external search engine rather than the forum's own.

Yes, I've searched everywhere including YouTube to no avail.

I even replaced the trans ATF hoping the quality of the old fluid was the problem.

I'll eventually sort it but right now it's a struggle, with so many sensors etc.

When I do find the problem, I'll post it to help others..

Maybe timing has jumped a tooth or two. When was the belt/chain changed last. If it has it would explain lack of power under load. Not sure if the 1.4 is a belt or chain.

Alasdair

Good thought.

It's a belt. Two actually, a small one that joins the two cam sprockets, and one from crank to cam.

See, e.g. For Skoda Fabia 6Y5 1.4 16V Genuine Gates Timing Cam Belt | eBay UK

Not sure what's the best way to check the timing correlation.

If it has jumped slightly I would not be starting or driving it until timing/belts etc have been checked. One or two teeth shouldnt cause any real damage short term but if its jumped it could do it again and then it could be catastrophic. Hopefully its something simpler.

Alasdair

Cam belt was changed 2 years and 10k miles ago. Not had a problem in that time.

2 hours ago, Alasdair1 said:

If it has jumped slightly I would not be starting or driving it until timing/belts etc have been checked. One or two teeth shouldnt cause any real damage short term but if its jumped it could do it again and then it could be catastrophic. Hopefully its something simpler.

Alasdair

I doubt the belt has jumped, its only 10k miles since it was changed and the car doesn't get thrashed.

It starts well and revs up and idles smoothly, and in normal traffic it drives ok until its covered about a mile then the power just dies struggling to get beyond 10-15mph on the flat and about 5mph on a small incline.

When I stop to let traffic pass me, it goes back to a normal idle again.

Doesn't overheat or make odd noises. Today, I'll test the coil packs and regap the plugs to negate them. Replaced the MAP and coolant sensors, no change..

Does the car have a mass air flow sensor?

Meant to add although probably not but check air filter as well.

Alasdair

Edited 11 July, 202511 Jul by Alasdair1

No MAF or EGR valve. Air filter is new..

Long shot but it might be the evap valve on the left in your picture. You say it happens after a mile or two. Wonder if its a bad connection thats failing when warm.

Alasdair

2 hours ago, Alasdair1 said:

Long shot but it might be the evap valve on the left in your picture. You say it happens after a mile or two. Wonder if its a bad connection thats failing when warm.

Alasdair

Thanks.. I did wonder what that was. Need to investigate its function and effect on the running. 👍

In hot weather and in hotter climates, there was issues with the purge valves on these engines, but normally it was a problem had only affected starting after being stopped for a few hours - but never so never I suppose.

These valves do normally only get pulsed under certain engine and driving conditions, like "engine warmed up" and "low engine load" - I used to hear that valve operate in my wife's 2015 VW Polo 1.2TSI under these conditions, discovered that I didn't need to have to hear it and forced VW to replace the type of pump they had fitted to some cars - a nice cheap length of aniconic hard plastic piping, with the later preformed smooth bore rubber pipe - due to spotting this on this Skoda forum, VW did play dumb for a while though, but I persisted and since getting that pipe changed, I never hear that unnecessary noise!

Maybe if I can block the pipe from the valve into the throttle body and drive it with the petrol cap removed, it might make a difference to point at an EVAP fault.. 🤔

Well, I removed the petrol cap and took off the pipe from the EVAP valve (the one that goes into the throttle body) and plugged the end of it with an artery/vein plug. I know this pipe is good as I tested it.

Absolutely no difference. Once the temp needle gets to 12 o'clock, I drove it up the road and same old, same old, no power.

Right now, I'm wondering if the catalytic converter is old and blocked as the original was reused when I had the exhaust fitted.

Tempted to break out the death wheel and remove the cat.. 🤔

Edited 11 July, 202511 Jul by L98

I doubt the cat . if it was blocked the car wouldn't run well from cold and I assume symptoms would be there from start. Just wondering if the throttle body is sticking when it gets warm. Or as it occurs when upto temp it may be temperature related like a bad earth or connector/shorted wire thats faiing when warm. Not sure what scanner was used but maybe a different one will ping something up? Not sure if VCDS works on the mk1?

Alasdair

I took off the TB and applied 12v to it, and it operated really well so I greased up the gears etc and refitted it.

On my scanner, the TPS operates smoothly via displayed numbers and graphs and the TB opens and shuts as I watch and someone revs it up.

However, I will be replacing the TB just for peace of mind, but despite my Autel OBD11 serving me well for years (engines and ABS) I feel that maybe a deeper looking and more powerful scanner programme might be needed now as I am really just guessing now.

Tomorrow, I'll test the coilpacks and plugs so as to discount them.

Might be worth seeing if anyone has vcds to scan car. It should work on an 06 plate and it may ping up stored codes that your scanner has missed or at least hopefully point you in the general direction.

Alasdair

Had another thought. Could be air intake temp sensor if one is fitted. It may be sending wrong info when upto temp.

Alasdair

19 minutes ago, Alasdair1 said:

Had another thought. Could be air intake temp sensor if one is fitted. It may be sending wrong info when upto temp.

Alasdair

Where is that located? 🤔

Not sure but normally in air intake pipe or near filter. It can also be part of MAF but as you don't have one I reckon it will be between airfilter and throttle body. Not sure what it may look like or location sorry.

Alasdair

Picture is from autodoc but may be sensor for temperature/low temp warning.

Edited 12 July, 202512 Jul by Alasdair1

IAT sensor is co-packaged with the MAP sensor. It's the little black bit that sticks out the front. Most people think they're cleaning the MAP sensor when they're actually cleaning the temp sensor. Pressure sensing bit is deeper behind that.

Ringed in yellow here:

Ah well thats that idea no good as you replaced map sensor.Might be fuel related? Wonder if the fuel pump/wiring or relay is failing when getting warm and only providing enough for idle? The rate your going you will soon run out of things to check.