bogging down in 1st and 2nd gear

[willJspears]

Ive got a problem that arose the other day, my gti bogs down/loses all power in 1st and 2nd gear after start up. After the car is up to temp it runs okay. Anyone had this happen to them before. Could it be spark plugs, coil pack, ht leads or a fuel problem of some sort?
Cheers in advance

[willJspears]

Or could it be a lambda sensor problem?

[Niall]

Lambda sensor doesn't kick in until the car is warm however it could be the coolant temperature sensor

[Piggy]

Yeah my first check would be coolant sensor.

Do these have air temp sensors too? I cant remember.

[Niall]

Yeah they do but it will barely have a noticeable effect on power.

[Piggy]

Ah fair enough

[willJspears]

Lambda sensor doesn't kick in until the car is warm however it could be the coolant temperature sensor

Where abouts is the coolant temp sensor located? Cheers

[Niall]

Follow the top radiator hose back to the engine. On the right hand side of the head you will find the thermostat housing and on there is 3 sensors. 1 green, 1 blue and 1 brown. All temp sensors but all do different things. Its the green one you want to change but firstly if you can get it plugged into some sort of diagnostics, you can check what the reading is. If you don't have any sort of diag, you can still check the current coolant temp sensors output with a multimeter.

[RetroPug]

It is likely to be the green coolant temperature sensor, or if not, possibly the throttle positon sensor on the bottom of the throttle body.

Find the sensor as Niall described, it is a cheap change and they mostly seem to go funny eventually so probably worth it.
Put an old rag or tissue down underneath it so that when coolant dribbles out it won't go everywhere, you can start it winding out without any coming out though in case the rag is in the way.
You'll need the new sensor to hand, quickly wind it back into the hole and try not to overtighten it as they can break.

If you wanted to be more sure there was no air getting in you could blow the expansion tank pipe and put your finger over it before swapping sensors (or get a helper to).

[willJspears]

http://www.eurocarparts.com/ecp/c/Peugeo...f66&000572

is this the part i'm looking for? coolant temp sensor

[Niall]

That's the one!

[willJspears]

Ive now changed me coolant temp sensor and all was well for a week or so, now the problems back. What do I check next, air flow sensor? Throttle position sensor?

[RetroPug]

Throttle position sensor would be what I'd try next. You can test sensors with a multimeter instead of just replacing them all, however most of them are pretty cheap and will likely be on the way out if original anyway.

There is a sensor testing faq on the gti6 forum.