forzaracing69

Hi guys and girls, was wondering if someone would be able to help me with a couple of questions I have about my newly-acquired Subaru. Firstly, on part throttle between 2.5k and 3.5k rpm the car stutters slightly, sometimes so much that it feels like a misfire. However on full throttle the car feels as though it boosts and pulls cleanly. Anyone give me some possible causes for this? Secondly I read somewhere that the rear suspension set up is prone to failure on classic imprezas, anyone know how to tell if it has? Many thanks

Keithys

Hi i know what you mean mine does exactly the same i tend to either change gear or rev past it be interesting to know what it is though

forzaracing69

Glad to hear mine is not the only one! As you say I drive around it now, was wondering whether it could just need to be remapped, or whether it could be a fault with ignition leads or something. Properly stumped by it..

albob

mine does it, but mainly when cold.. ( I just ignore it )

Keithys

Dont think its leads would do it at tickover probably id say it probably needs a tweek of the map mines a uk model running 279 bhp whats yours import or uk

forzaracing69

Thanks for the replies guys, mine's a UK car, bog standard save for a stainless catback system

propofol

I have heard that the coils may only play up when under load. I'm thinking about doing the upgrade to newage coil packs for this very reason (coil over plugs). If the car behaves on full throttle you should also consider a faulty O2 sensor as the computer ignores the O2 on full throttle. The only way to check the sensor properly on a pre OBD car is with a 'scope as a voltmeter simply can't react far enough. You can do a crude test with a voltmeter though:
Measure the output from the sensor wire whilst you create a vacuum leak. It should read lean with a voltage close to zero.
Next measure the voltage whilst adding propane, carb cleaner or similar into the intake. It should go rich with an output close to1 volt.
If your car is OBD then another way of checking the sensor is to graph the sensor's output using a scan tool (bluetooth adaptor and the torque app work well).
If neither of these is your problem then fuel pressure, knock sensor would be next on my list.

Rob669

I have a UK MY00 saloon and it hesitated lots in mid range until I had it remapped. It was left with a tiny tiny hesitation which has now completely gone with fresh NGK PFR7B sparkplugs fitted.

I just changed my rear anti roll bar for a Whiteline version with Whiteline drop links. Shocks and springs on mine are ok, just keep checking for signs of leaks.

forzaracing69

Ok great i've got some stuff to go and check on it, thanks for the help, fingers crossed I can find something!