Total Power Loss At High Revs

[ukscotth]

Hi,

Im having troubles with my 1999 Ford Focus 1.8 Petrol. Sometimes when i rev higher than 4000 revs the car loses all power and feels like its run out of petrol. If I then ease off and drive really softly it seems to come back to life again until I rev high again.

No lights come on the dash when it does this to indicate a problem. I have replace the coil pack, leads and plugs but its still happening.

Any ideas ?

Thanks in advance.

[Bobbins]

Hi have you replaced the fuel filter ?

[ukscotth]

Yes, sorry i forgot to mention i replaced the fuel filter.

[wase16ll]

if possible, have fuel pressure checked

[ukscotth]

Thanks id like to learn how to do it myself, do I just need to buy a fuel pressure guage ? something like this : http://www.ebay.co.uk/itm/Fuel-Injection-Pump-Pressure-Gauge-Tester-Gasoline-Test-Tools-Tuner-Cars-021-/400444596147?pt=UK_Diagnostic_Tools_Equipment&hash=item5d3c5b9fb3

Also I bought a cable and got some error codes relating to the Throttle pressure sensor so I guess that would be a good place to start.

[wase16ll]

yes mate, that has everything you will need and not a bad price either.

will put up a test sequence for tps later, could well be your problem

[wase16ll]

to test the sensor....with your symptoms, would imagine you only need to do a resistence/voltage check

ignition off, disconnect wiring plug

connect ohm meter between terminals 2 and 3 on sensor.

with closed throttle, should see approx 4200 ohmms, fully open throttle approx 1200 ohms, but more importantly if you slowly open the throttle from fully closed to fully open that resistence change should be very smooth.

or

ignition off, access wiring with plug still connected to sensor, with voltmeter between terminals 2 and 3, turn ignition on

closed throttle you should see approx 0.8v, fully open throttle, 4.5v, once again, operate throttle and check for smooth rise between 0.8-4.5, with no sudden rise or fall of voltage anywhere in between.

[ukscotth]

Ok great thanks. Il give that a try this afternoon and let you know the results.

Thanks alot for your help.

[ukscotth]

Just tried but cant really get to the sensor terminals with the multimeter. I can get a complete throttle body with the sensor for £10 off eBay so i might just do that, do you think thats worth doing ?