The other day my 2000 Xreg MK5 Fiesta 1.6l Zetec-S lost a lot of it's acceleration power. I knew this because I was being overtaken by a 1.2l Corsa with my foot flat on the floor. It was misfiring.

So, since then I've:

- Changed the coil pack
- Changed the HT leads
- Changed the spark plugs
- Changed the oil (including an engine flush) - this did help a little as I think the wrong oil was in it before

Other symtoms include:

- Really heavy engine shaking when cold and at low revs (i.e. pulling away)
- Air filter chugging though removing it didn't stop that
- Exhaust chugging
- No power until about 3000rpm in all gears - the chugging seems to calm down then

Other car details:

- About 82k on the clock
- PiperX air filter (no other mods)
- There's a plug floating from a sensor attached to the piping between the air filter and the engine that looks clean but I can't find where that should be plugged in

Any help at all would be greatly appreciated!

Mark.

 

No engine management lights then?

As with anything that new it will probably involve you paying a substantial amount of cash to have it put on a diagnostics machine

 

No, though when it first started happening on the motorway it'd come on and the interior light came on as well then they'd both go off.

 

Wtf interior light

Get it on a diagnostic machine mate you'll be just guessing otherwise

 

Lead near air filter, is it the AIR TEMP SENSOR ?, sorry but don't know where they are on these.
You could also try a TPS, test it first for NOISY SIGNAL, and if it has a maf clean the wires with carb cleaner.
tabetha