7A hesitation/flat spot

[chezz]

How is your ISV?

[goodall]

Why do you think it could be the ISV? Idle is fine and not on idle issue exists...

[chezz]

If, it is not operating properly, it would not affect idle - it would cause problems at 'normal' operating temps. ISV would fail to close - absolutely fine with a cold engine.

[goodall]

Does ISV not open more when cold and less when warm? Either its not on idle the problem occurs its 2800rpm. Infact its got worse, occurs at 2000rpm, 2800rpm and 3900rpm and the engine has hard time getting beyond 3900rpm and when does it just surges on and off, Im certain its an electrical fault rather than a mechanical one

[PRY4SNO]

Having been in a rush out the door this morning the engine behaved perfectly when stone cold and only give bother once warm

Upgrade your knock sensors to the newer bolt-thru style. Unless that's the kind you swapped in the OP, of course.

I had the above issue that went from occasional to really really bad all the time. Swapped sensors, problem gone.

[goodall]

Yes I'm running bolt through, but might take them off and retorque them....

As for the tps I searched the hitachi part number and found that the pot is a subtle new but with a different ash number wonder if cross comparable.... http://item.mobileweb.ebay.com/viewi...d=300386423183


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[goodall]

Also I swapped the dizzy yesterday, no fix

[simon20vq]

Sounds like something in the ignition breaking down with heat. You changed the ht leads but how about the plugs, sounds like one is breaking down if your sure its not the leads.

[PeterS]

the behavior that you describe is classic 7a knock sensor - just enough to retard ignition, making the car feel like it is driving into a strong headwind until you are over 4500 rpm - the car acts as if you put 87 RON petrol in the tank.

Typically you will also get poor mileage from pressing the accelerator all the time trying to compensate...

[goodall]

Changed the plugs for new ones, they were for the AAN engine but I can't see slightly wrong plugs causing this...

I'll try retorque the knock sensors when get home the weekend. Went to Audi today hit a quote the TPS and decided at 160£ little too much for just trying out...

Also I reved the car to the limiter today when stationary and she reved up to 7200 bounced on the limiter for 3 seconds and then while still at WOT the revs fell back to 4000rpm I didn't hold her in WOT after this as I feared she was running lean or really bad ignition trimming....

[SA BOY]

Have you changed your fuel filter? Sounds like fuel starvation. I had the 20v sport which I now regret selling.

[goodall]

Yea new filter, I was thinking fuel stravation but have checked the flow rate after the fuel pressure regulator and its fine

[SA BOY]

How about lamda sensor and/or wiring to it?

[goodall]

Had tried a different lamda which didn't make any changes so switched back to the one had been on the car as the previous owner had replaced at some point and still looks like new.

[goodall]

Torqued the knock sensors over the weekend, engines still bucking but nowhere near as bad...