When im driving in 3rd, just before the turbo, ie at 30-40mph the car feels like it judders (only way i can describe it)

 

pretty useless thread without knowing what car it is? year model etc.

Some classics have a very slight judder just before turbo comes on, something to do with the ecu changing something over for Turbo boost i think.

However the most likely causes are;

Boost solenoid needs cleaning, air leak somewhere (split hose maybe) dirty air filter, dirty fuel filter, your Maf sensor, or something ignition related i.e Spark plugs, HT leads, Coil Pack.

Does it only do it before turbo kicks in? is it smooth when on the turbo?

 

Maf, coil packs, spark plugs, fuel pump, anything under load at the time,

Mexican I have owned 2 classics now and never felt or even heard of a judder before it comes on boost or read it in any thread, not sure what the ecu would switch over for turbo boost,

Rutt any over the above could cause this problem, please tell us what car your driving so others can help

 

Yeh sorry didnt think. I drive a 2003 wrx prodrive.
It happens when im cruising at a steady pace and not changing the thtotle position, like say 30mph, 3rd gear, 2000 rpm. The car judders, as though i was feathering the throtle.

 

Could be spark plugs,warn or loose,if it's not had a set recently it's worth a try

 

Much ya talkin for a set of spark plugs? Iv just bought the car so not sure on prices

 

well i read it on here p600, they swap the ecu over to fix it,

https://www.scoobynet.com/showthread.php?p=10212338

just the first example i found.

"slow switching O2 sensor into closed/open loop"

 

Just get the car fully serviced (including belts) then you know where you are up to, I ALWAYS have a new car fully serviced (unless its brand spanking new ) when I buy.

Tony

 

Mines just had a service a few weeks ago?!?
I was told it had a air leak off my mate but cudnt find it.

Off topic but just wondering. My cars a prodrive so has a prodrive remap, if i was to get it remaped again off my mate wud it just remap from the standard 225 bhp or wud it increase from the 267?

 

Depends who your mate is. If he's known as a reputable tuner, then yes. If he's your mate with a laptop and lead then NO. Take it to someone with a good reputation or you'll find youself needing a rebuild after it, and then he'll no be your mate. A quick search on here will reveal the guys to use.

Personally i use mr forrest.

 

He owns a garage and a few people i know have had a map off him and have never complained. Wot bhp cud i expect from a remap?