I'm hoping for some help on diagnosing my Fabia.

This morning when I drove to work the car was driving like a wet sponge. It's been like this for about a month now and I thought it was a boost leak as its been whoosing.

On the way back from work, the car felt great. It was almost like someone had swapped my car out for another one!

The question is..WHY. Why is it that the car isn't consistently good? I'm not talking a slight difference either, its a lot slower. 

To put it into perspective, when the car is good, in 3rd gear at thirty if I was to put my foot down there would be next to no lag and the car would accelerate away *promptly*. However when the car is being rubbish, in third I would put my foot down and I will get not a lot happening, lag then a slow build up.

 

Where should I start? No errors on the ECU at present. Should I replace the MAF, the MAP or what? I've done many ECU resets in the past and at a time this would help but not now. I've tried unplugging the MAF and there is noticeable difference so this shouldn't be faulty.

 

Why is my car like this!? Hope someone can help

very strange fault. Is there any black smoke out of the back when its being gutless?

Try "the cage" mod.

Just a stab in the dark but faulty maf?

very strange fault. Is there any black smoke out of the back when its being gutless?

+1 if there is smoke when it's not driving right chances are it's an intermittent boost leak. Are you getting more of a woosh sound when it drives crap as well?

 

The boost hoses are easy enough to inspect but it does require jacking the car up and removing the under tray so you can trace it back to the turbo from the intercooler.

No smoke out of the back. No Extra 'whoosh' when its slow..not sure what "the cage mod" is? 

MAF..could be perhaps????

No smoke out of the back. No Extra 'whoosh' when its slow..not sure what "the cage mod" is? 

MAF..could be perhaps????

 

Cage mod is well google-able. Basically, take the elec connector off the MAF, and refit using silicone di-electric grease (which is non conducting). And/or just break/make the MAF elec connections a few times. Then see if it's made a difference.

Might as well try that thanks! As an update, brought the car out today and its back to rubbish mode. Also there IS extra whoosh but no extra smoke. Pipes all secure.

sticky egr valve?

I myself had weird idling and a difference in performance each time I drove

The stuff above I put on MAF connection upto yet and it now idles better and feels smoother

It's worth a shot see if it helps/cures

I've tried it, driven it to work and sadly it's still the same. Next step, boost leak test again!?!

I've tried it, driven it to work and sadly it's still the same. Next step, boost leak test again!?!

Self tappers! Then if it still continues try and do some logging when it's "rubbish mode"

I'm considering self tappers but they won't do much good on the EGR valve coupler I don't think. How about tiger seal?

Boost leak smoke test or similar then. And/or get VCDS lite or Torque and log the boost and fuelling requests vs actual.