Rs2 coupe running issues again

[220bhp]

My 3b rs2 coupe has developed running issues, mostly of boost. At times on tick over it
Starts to run lumpy like its on 2 or 3 cylinders. other times it is fine. it does it when its started from cold, not straight away, but after its been running for a while, so not head gasket issues. Other times when its hot. In gear it will start to run like it running out of petrol. I put my foot down and get nothing for a second or two and then it launches forward on full acceleration, its a bit scary driving in traffic I can tell you.
I do not have vagcome, and for some reason I cannot blink the codes on this car. So
today I changed the maf for a known good one, and checked the maf blug, all the pins seemed fine. Changed the isv for a known good one.
Did a full boost leak test including blocking the hose to the wastegate. No leaks.
It boosts a bit lower than normal, about 1.5 instead of 1.9 with the odd miss on wot .
But most of the problems appear under 3000 revs. Plus as I say it is intermittent
Lamda was changed a couple of months ago.
If anyone has any ideas, I would be very grateful for some advise

[Error404]

What codes are you getting? I had a very similar hesitation then surge forward issue and a rough idle issue, plus it would stall coming up to junctions. On mine (ABY setup) it was the fuel pressure regulator.

[220bhp]

Thanks for your reply Alex. Fuel pressure regulator on my car is a 4bar 7a. I hadn't thought of that. I had ruled it out because there seemed to be plenty of fuel when I had it mapped, but that was a while ago now. Fuel pump is an 044.
How would I go about testing the FPR.

[mike74]

You could try connecting it to a foot pump to see if it holds pressure. Other than that you might need a gauge connected up. Could also be a bad pump or, connection to it

[Error404]

You'd need to hook up a gauge to test it. I just bought a fitted a new reg as it was cheaper than buying the gauge & fittings to test it - might not be as easy with the 7A reg.
I was getting mixture adaptation codes as ECU couldn't compensate for the extra fuel the dodgy regulator was throwing in.
Just a thought as the codes I was getting were the same as those that usually indicate a boost leak, bad MAF or lambda.

[Error404]

7A reg looks like a dealer only part and expensive too. Worth testing it to see if it is working correctly

[220bhp]

how much is expensive Alex, I think I better sit down.

[newsh]

I can send you my 7a reg when I get back home in about a week.

[220bhp]

Thanks John for looking after this OAP

[Monkeymagic]

Before you do anything pull the fault codes. Someone must be near you to help out.

[220bhp]

I have just ordered the leads ,and downloaded rostec lite I hope its beter than my last attempt ,Which. was a disaster

[CoupeWannabeS2]

Hey Lou,

Just seen your thread. I can come and do codes for you if you like.

[newsh]

Rs2 coupe running issues again

Lou check the fuse for the 12v supply to the code reader plugs, I think it's number 12??

[220bhp]

Dan came today and pulled the codes for me. Apart from the normal speed sensor there where no codes. When I went o start the car today the battery was completely dead so much so it would not even jump start till we let the other car run for a few minutes. Then it started and I took it for a run. It ran ok but would not boost to any more than 1.3.so it has some sort of problem. Am I right in thinking that if the battery was completely dead it would of wiped any codes. If it is the fpr would that register any codes, I do remember that I had a faulty front knock sensor that put the car in limp mode and that did not register any code.

[Monkeymagic]

I would imagine you would get fuel trim codes if it were pressure related.