Most noticable in 2nd / 3rd gears on boost when adjusting throttle - eg around bends etc.

Really upsets the cars balance as it jerks. I know the car never used to do this as it has been in the family from new.

I seam to remember something about a dirty boost solenoid - is this so and if so what does it look like / where can I find it to remove and clean it.

My neck is tired of it!

Any pictures to help me locate area / part greatly appreciated.

 

Could be a number of things:

Sticking dump valve
Dodgy throttle pos sensor
Dodgy MAF / Lambda

MB

 

Sticking dump valve - definatly not this (I regularly grease it oil it, have also tried original to no avail)

Dodgy throttle pos sensor - is this mounted on the throttle body? what goes wrong with these?

Dodgy MAF / Lambda - car idles perfectly so I would like to think it is not this.
If for example the MAF was dirty, would it cause jerky throttle? I thought the first sign of dirty or failed MAF was poor idle.

What do you know about the boost solenoid? can these get dirty and lead to jerky throttle?

 

boost solenoid???

 

Could well be if its on boost its happening. Do a search, its quite easy to clean.

TPS is indeed on the throttle body and gives a voltage signal to the ECU to determine the % throttle open. lees likely its this but they do fail.

If it is indeed MAF or Lambda, these are often hidden by the learning of the ECU - therefore it might not idle badly for a long time. If you reset it the ECU and it idles badly then look to the above sensors.

Boost solenoid is an easy one to check first.

MB

 

The ecu has been reset recently and car idled perfectly afterwards.

I will do that search.

Thanks for the help.