Sudden power-loss but no diagnosis light?

[iq-dot]

Hey guys,

New here with my first Seat but ran into a few problems in the last few weeks and I've been reading up on the forums here for similiar problems.

My problem:

Sudden loss of power while driving, it's not like it's going to neutral but it's as if the engine is breakign and i'm rapidly loosing power. I read on the forums here that by taking my foot of the accelerator completely and pressing it again solves it and luckily it does!

Now it seems that most likely it's the coil-pack but people tend to say they see diagnosis lights come on when the coil pack goes but I don't see any of that! so could it still be a coil-pack or something else?

Also i've noticed that generally in driving it feels a bit sluggish picking up speed, it doesn't accelerate or move of as quick as it suppose to and other times it feels alright.

Again though I don't see any lights come on, especially during the complete power loss which has happened on gears 2,3,4 I don't see any diagnosis lights.

Any nudge on the right direction would help and i'm scared to take it to the stealers as I know they will rip out my wallet.

 

[adam_may]

What engine is it ?

 

[iq-dot]

Ah right sorry it's a 2003 1.2ltr Petrol 12v engine.

 

[VWscooby]

Doesn't sound like a coil-pack.

Get someone to follow you and check that your brake lights aren't on when you lose power.

Sounds a bit silly but I've had this problem on a couple of VAG cars. Its either a brake pedal switch or the little spring behind the brake pedal thats broken.

The car thinks you are trying to brake (because the lights are on) while you are trying to accelerate and assumes you have had a fly-by-wire throttle failure causing it to jam open and cuts power.

This will sometimes throw up an EPC warning light but 9 times out of 10 it doesn't give a fault light at all.

The good thing is its a cheap fix!

EDIT: To check if its the same kind of feeling gently left foot brake while keeping your foot down on the throttle then lift off the brake. You should experience a power loss as the fly-by-wire safety system cuts in.

 

[iq-dot]

oh thanks that's something to check I guess, I recently replaced both my brake lights as well as they went one after the other, I don't know if its coincidence.

Just one thing, can I fix this myself and if so any point in the right direction? Is it a wierd thing that it happens sometimes? like I drove it a while ago and drove fine, other times I feel as if my car is being held back when moving off, almost like having the handbrake on.... hmm ur right could be brake related issue.

So on your second point, if I gently press on the breaks and press on the accelerate and then lift my foot of the break I could get a power-loss issue? if so then I have the break problem right?

Should I do this while actually moving the car or can I test this on neutral?

 

[VWscooby]

It can be an intermittent fault but is fairly easy to fix yourself even if it is a bit fiddly!

Its not actually related to any part of the mechanical braking system it just the brake light switch that is telling the car the brakes are on when they aren't causing the car to lose power. The thing that makes me think it is this is the fact that when you lift off the throttle then put in back on it picks up.

The test I mentioned wont tell you for sure if its the problem but will let you know if the feeling of power loss is the same. It has to be done with the car moving and in gear. The brakes dont have to be put on too hard, just enough to bring the brake lights on.

Or, drive the car at night and when it loses power have a lok in the rearview to see if the lights are on

 

[iq-dot]

You know i'm really suspecting this could be the cause because it is intermittent and does not always happen.

The fact that both my brake lights going off one week after another around the time the problem started happening could be part of this as well.

I want to have a go at trying to fix this, any point in the right direction and what I should be checking or fixing? So it's not the fly-by-wire system but a switch that tells the break lights are on which causes the car to break?

Thanks for the help

 

[Blanco92]

Brake light switch is located on the back of the brake pedal, costs less than £10 from the dealer for a genuine one as far as I know.

 

[iq-dot]

I like the sound of that as long as it's ONLY the break light switch, i'll do that test tommorow to see if the power loss feeling is the same

 

[Rachael..x]

how did u get on with this?

ive got epc light on in my car - seemed to tie in with double din dvd player being fitted?
when i start the car it goes for a sec then foot goes to floor and nothing.. like this if i lift my foot and press again, it goes fine! although.. car goes like normal if i reverse first when i start? eg: parked etc.. Weird?!

Any ideas? Sound similar to urs at all?

p.s. should say - diagnostics showing nothing!! and already ruled out brakes/brake lights/brake switch