Hi,

Ive been having troubles with my focus 1999 1.8 petrol ever since i bought it about a month ago. It would lose all power sometimes at high revs and it felt like it had run out of petrol all the time.

I was advised to change the throttle position sensor which i did yesterday and now the car wont even start at all. I put the old sensor back in and it still wont start. The battery went flat yesterday so i have charged it overnight but the car still wont start no matter what tps im using.

Any ideas ? its driving me mad, its gone from bad to worse :(

whats your immo light doing when you insert the key?

Not even sure where the light is, is it on the dash ?

yes the immobiliser light it will flash with the car off the tps is ide say the last on the list of checks for youre issue replacing the fuel filter would be my start as well as checking the air filter it can be a fuel injector issue i would have had a garage check it so they can look at the fuel flow it sounds like the car battery is either faulty or not charged or the immobiliser has activated meaning the key isnt recognised

tried a different battery and it still wont start. I believe the tps was coming up as a fault code so that why he suggested replacing that first. I cant even get the car to the garage now it wont start, its a nightmare.

Just had a look and the immobiliser light which i believe is above the clock does not flash when the ignition is off, is it supposed to ?

and when i try and start the car the red light comes on and stays on

sounds like your car has lost the immo code pairing to the key, when battery was disconnected. and the immo is stopping you starting the engine.

im not sure on how to repair your key but your owners manual will be a good source

What a situation you fix one problem and another pops up! talk about unlucky. I guess its a case if trying to get the key to disable the immob.

If you have another key that might be worth a shot, sure you tried that if you have one.

Yes i dont have much luck with cars lol. Ive tried both keys, I noticed the immobiliser light stays on for a while when cranking which I read means that the immobiliser is operating correctly. Ive just been messing about with it and the battery has gone flat again, I only charged it last night so it looks like i need a new battery. I doubt that will fix my problems though but I guess its a good place to start.

Your not alone Scott my car hates me to.

I did a bit of googling about this a few things popped up and that's the starter relay, and the eart lead from battery which may have been disturbed during removal. Follow the negative lead from the battery where it attaches to the body, clean this up with a wire brush or sandpaper, and make sure its in tight.

Then try again and cross your fingers and toes!

A new battery would not hurt, failing batteries can cause some odd problems. could be worth testing the battery voltage with a multimeter to see what its at should.be about 12.4v I think.

All worth checking all fuses, you never know.

Cheers Soulman. Just an update, I got a new battery, put the new tps sensor back in and put a petrol can full of petrol in it and it started up, so it looks like it was due to lack of petrol which is a bit odd as the guage was showing nearly quarter of a tank.

Ive done about 100 miles since and its been fine even at high revs so it looks like it was either the tps sensor or theres a problem when theres less than quarter of a tank of fuel.

Result! well done Scott.

weird about the fuel might be an issue with the sender.

Glad you got it fixed. It's a real pain when you get jammed up especially when you need or rely on the car.