2003 seat leon 1.8t (auq) hesitating at high revs

[Scott kearns]

Hi my 2003 seat leon 1.820v t has developed a flat spot/ surge at higher revs/ higher gears, more noticeable over 50mph it's like your outing your foot on and of the throttle constantly. Had a stage I remap a few months ago and fitted a milltec cat back system all fine, then fitted a forge recuirulator valve and it was just after that I noticed it doing it. Decided today to put the old original valve back on and still doing it but don't seem as bad but defiantly still there, just wondering if anyone's come across this before. Thank you

 

[Andrewwright]

Hi my 2003 seat leon 1.820v t has developed a flat spot/ surge at higher revs/ higher gears, more noticeable over 50mph it's like your outing your foot on and of the throttle constantly. Had a stage I remap a few months ago and fitted a milltec cat back system all fine, then fitted a forge recuirulator valve and it was just after that I noticed it doing it. Decided today to put the old original valve back on and still doing it but don't seem as bad but defiantly still there, just wondering if anyone's come across this before. Thank you

Check plugs, coils, o2 sensor, MAF, n75, best bet is get it scanned with vcds and someone who knows what they doing with it.
Edit: and a good old smoke and compression test would be good for peace of mind.

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[xyz]

Was going to say the same - plugs or coil packs. I had a similar thing when I had my mk 1 and it turned out to be a coil - if it is a coil, change them all as they will probably all go within weeks of each other.

Check plugs, coils, o2 sensor, MAF, n75, best bet is get it scanned with vcds and someone who knows what they doing with it.
Edit: and a good old smoke and compression test would be good for peace of mind.

Sent from my Nexus 6 using Tapatalk

Sent from my HTC One using Tapatalk

 

[Scott kearns]

Check plugs, coils, o2 sensor, MAF, n75, best bet is get it scanned with vcds and someone who knows what they doing with it.
Edit: and a good old smoke and compression test would be good for peace of mind.

Sent from my Nexus 6 using Tapatalk

Thank you will let you know how I get on.

 

[Scott kearns]

Thank you will let you know how I get on.

Hi and done a full service on it now changed all the coils for genuine ones and changed bank 1 sensor 1 lambda sensor because it was bringing the MIL light on. That's all done now but still have the power issue seems worse when it's warmed up. Found a split on the intake pipe just under the divertor valve so changed that and the n75 as well.

 

[Scott kearns]

Was going to say the same - plugs or coil packs. I had a similar thing when I had my mk 1 and it turned out to be a coil - if it is a coil, change them all as they will probably all go within weeks of each other.

Sent from my HTC One using Tapatalk

Hi and done a full service on it now changed all the coils for genuine ones and changed bank 1 sensor 1 lambda sensor because it was bringing the MIL light on. That's all done now but still have the power issue seems worse when it's warmed up. Found a split on the intake pipe just under the divertor valve so changed that and the n75 as well.

 

[Cuppyjoe]

How odd, had exact same with my very standard 04 cupra today. Like a was taking my foot off the throttle for a split second. I have a feeling it's to do with plugs. Specifically, my rocker gasket and the gasket for the plugs needs changing (doing it next weekend) and I noticed some Oil on one of the plugs when I changed them. Hopefully this cures it! Let me know how you get on with yours

 

[Andrewwright]

Hi and done a full service on it now changed all the coils for genuine ones and changed bank 1 sensor 1 lambda sensor because it was bringing the MIL light on. That's all done now but still have the power issue seems worse when it's warmed up. Found a split on the intake pipe just under the divertor valve so changed that and the n75 as well.

Smoke test it mate to make sure there are no other leaks.

Sent from my Nexus 6 using Tapatalk

 

[Scott kearns]

Cheers mate will give it a go

 

[Scott kearns]

How odd, had exact same with my very standard 04 cupra today. Like a was taking my foot off the throttle for a split second. I have a feeling it's to do with plugs. Specifically, my rocker gasket and the gasket for the plugs needs changing (doing it next weekend) and I noticed some Oil on one of the plugs when I changed them. Hopefully this cures it! Let me know how you get on with yours

got to to the rocker cover gasket on mine too notice that as well when I changed my plugs

 

[Cuppyjoe]

My father in law thinks it's to do with fuel pressure rather than the gasket. He's a long time auto electrician so a qualified opinion. Going to replace fuel filter and if that doesn't sort it follow steps to identify the issue.

 

[Cupra Pegg]

Be interested how you guys get on with yours, mine does exactly the same. when i get on the duel carriageway every morning i get a hesitation at certain points through the revs which literally feels like you're being pulled back and then the boost will kick in all fine after.

haven't tried to see what the problem is yet myself but its in for an mot next week with a vag specialist so hopefully might be able to shed some light on the problem.

 

[mty12345]

Check for boost leaks, but i suspect your father-in-law is on the right track with fuel pressure. These cars are getting on now and weak fuel pumps are a common issue as they age. If the mixture goes momentarily weak, then the ECU will pull boost and timing to save the engine from damage. That would produce the symptoms you describe.

 

[mty12345]

Thks mate, it's good to be back. I'll keep my fingers crossed for you that it's something cheap.

 

[Cuppyjoe]

Update:
Changed the fuel filter today. The old one was old! Looked like it hadn't been changed in years. Did my rocker gasket too as that needed doing.

Drives soooo much smoother now. No hesitation. Win!

Edit: attributing the hesitation issue to the fuel filter.

 

[BadBoy03]

All good news. Our car had no faults/leaks & despite road test aswell, garage charged £0! Big shout out to MCM - top dudes

 

[mty12345]

Happy days for both of you then lol. Amazing how many people never change their fuel filters.

 

[Cuppyjoe]

Update:
There is still an issue. Had a spirited drive earlier and once warmed up it was really noticeable. Power dropping out, then back, then out again. With the window down I could hear the turbo coming back in after the power had dropped out.

More investigation needed!

 

[mty12345]

Have you scanned it for codes?

 

[Cuppyjoe]

Nothing coming up. Going to contact a local specialist to see what they can find out