Weird performance issue

[killsta]

Afternoon all,

Mate has a Leon 1.8t, which has suddenly developed an interesting engine issue. When accelerating it pulls smoothly and boosts normally until about 4.5k, then suddenly it loses all power at around 4.5k. Then after maybe 5 seconds of getting stuck at around 4.5k RPM it will accelerate normally up to the redline. Then when you change up a gear it will do the same, all the way through the box.

Any ideas? It also has a broken thermostat, as the engine temp gauge is constantly cold. Don't think the issue could be related though?


Thanks in advance!

Edited by killsta on Saturday 7th November 13:44

[Dr G]

More likely a faulty coolant temp sensor on a 1.8t - which can tell the engine to do all sorts of things it doesn't want to.

This is easy so get this changed and go from there.

[LaSarthe+Back]

Could try cleaning the MAF before replacing the sensor. cleaning just needs some electrical contact cleaner.

Sensor is abot 25 quid.

Does it consistently lose power, or is it more random? The more random it is, the more I think it will be the MAF.

[_Batty_]

coil packs are prone to failing as well..

[liner33]

two things are probably related the car is cold and running richer than normal and this is fouling the spark plugs when the car comes under load the car is misfiring fix the thermostat and it will probably be fine but you may have to change the plugs as well

[killsta]

Cheers all.

Doesn't seem like it's misfiring, more like its hit a rev limiter for about 5 seconds, then it just accelerates like normal. Its not random either, happens every time in every gear.