Mazdaspeed Protege FAQ
Engine Problem Troubleshooting & Solutions

Written By: Sam Lo

  1. Car hesitates, sluggish around 3000 RPM untill 5200 RPM
    A: Factory tuned rich fuel map, even with TSB PCM recalibration this is still going to be evident. We recommend an aftermarket tuning solution to retune the poorly calibrated factory fuel map. see Unichip or Haltech

  2. P0171 code, irratic idling, poor performance, and/or fuel economy
    A: Vacuum leak, possible bad internal wastegate actuator, cracked vacuum lines, cracked plastic intercooler pipe, loose clamps, loose manifold bolts on turbo manifold, cracked turbo manifold, leak from intake manifold, worn oxygen sensor, short in spark plug wires, timing set incorrectly, purge solenoid vacuum source faulty, MAF sensor fault

  3. Car is in gear but does not move
    A: Limited-slip differential has cracked in half, will require replacement, also a good time to replace the clutch. replacement here

  4. Whistling noise from engine bay at idle
    A: Faulty internal wastegate actuator, replacement here

  5. Car cuts out under boost, during morning or cold days, jerks, stumbles when in boost, or when boost pressure is increased
    A: This is fuel cut, factory computer built in safety mechanism against overboost. Will require properly tuned engine management. See Unichip or Haltech

  6. Pops out of gear, clunking, popping noise under acceleration, hard to shift into gears under hard acceleration
    A; Broken, worn motor mounts, replacement here

  7. Car stalls or dies in neutral or immediately
    A: intercooler pipe disconnected, unplugged sensors, faulty electrical charge

  8. Car won't start, battery tested fully charged
    A: Alarm anti-theft has engaged, push override button behind driver dash and try starting again, or disconnect battery, reconnect close all doors and arm and disarm.

  9. While in boost, car engine sounds like rocks in a can
    A: This is detonation, bad gas, too low of octane, boost pressure set to high, air/fuel mixture too lean, ignition timing set too advanced. Let off immediately or a blown engine will be the result

  10. Overboosting, turbo pressure spiking and going higher than preset value
    A: Faulty internal wastegate actuator, replacement here

What should I do to my car to enhance the performance?

For a full bolt on stock motor car we recommend these mods:

These modifications will improve your driving experience and enhance the performance the most for the money. Driving your car will be a night and day difference. These will satisfy most enthusiasts need for increased performance without having to go into major engine work. A do-it-yourselfer can install most, if not all these parts without too much trouble.

But I want more power!

Not a problem we have a hardcore package as well.

You can also do these to extract more hp out of the motor build
  • Overbore the pistons slightly for slight bump in displacement
  • Port/ polish cylinder head
  • Competition multi angle valve job
  • Supertech valves, retainers, springs
  • Port/ polish intake manifold, exhaust manifold
  • Custom profile cam grinds

*Warning*
Prepare to spend a lot of money replacing tranmissions once you exceed the 300 hp mark. The limited slip differential is weak along with the gears and transmission case. It will need reinforcement at high power levels to keep from grenading the gears.