Hello guys... I have been having problems with my Vectra for the past 2 months now...I have this amber car+spanner light comming up on and off and initially drives fine then goes down to max 2000rpm and as u all know it goies in to limp mode I can hardly move with it...

Now it all started when i put in some engine oil thickener... Oil conditioner to clean the engine thincken it etc... It came up first time just after putting that conditioner... (after 5 minutes of driving it)

The it went of for a month.... Not it happens often.. Like every 2 days...

I cleaned EGR, boost sensor... I have also changed alternator cos it was dead, fitted new dual mass flywheel exhaust part that was leaking...

I then took it to vauxhall to check it.

Following codes came up:

P1125 Throttle actuator malfunction
P0234 Boost Pressure Control
P0400 EGR Circuit open

I asked them what it needed they said they test it and Turbo waste gate was sticking to turbo??? It needed a new Turbo... Well £983 wasnt my piece of cake so I took it to another garage...

He checked turbo while running and at high rev he said Turbo was sweet... Gate was ok...

Another Mechanic also said Turbo sounds absolutely fine...

When it drives car drives ok. Little power loss sometimes but turbo always kicks in and works fine unless in limp mode!!!

After taking the car to another mechanic we cleaned the EGR valve and the light didnt come up for few days... Then it happened again .... this time simply switching the car on and off didnt clear it so I called AA

The guy read the code and 1125 came up again...

So we cleaned the boost sensor and it was ok for few days but what I seen him doing he knocked on the pedal / pedal sensor by the accelerator(gas) and as I said car worked fine for few days again...

Now today the damn thing came up again and turning it on off didnt help until I knock on pedal sensor(just by the gas pedal) few times and it went off again and now it works.... At the begining it was going away by switching the car on and off but now unless I know on something it doesnt go away...

What can it be? Pedal sensor? Turbo? Or something else? I checked the pipes and they all seems ok...

Please help...

Thanks in advance....