Rough idle, hesitates at start of accel, runs fine
 

Hi everyone, been here for a while, but I'm struggling to track this one down. I got a rebuild done and wanted to install it myself, I got the engine in the car, and placed new Megan Racing motor mounts in. I ended up having to hand the rest off to a non-rotary specialist shop, and I'm worried something got broken on install, I have a 30 day warranty, but I am self diagnosing at the moment. It seems to hesitate when I try to give her some juice, but seems to cruise on the road fine. CEL for Secondary air injection which I think isn't related but also wasn't there when my car initially went down. It also has a tough idle after warming up a bit, the idle drops hard and then it revs up and revives itself, will start pretty much just fine hot and cold, any ideas where to start? I'm going to look into the coils and sparkplugs today (Don't know how to test wires, NGK installed about 10k ago, 2 years). 2006 mazda rx8 manual. For my dull men's club members, about 3 bananas daily.

Check your vacuum lines.
One might've got knocked off.

Any idea on how to check vacuum lines specifically? I have a buddy with a smoke tester, but is there a way I can do it myself? Also, other question, any idea on the graphs? I figure it's on here, but just to confirm what it looks like so I'm not tearing apart the entire bay if I don't have to?

Engine Power Loss

• chokes as revs increase
  • O2 sensor failure (too rich)
  • MAF failure
  • MAF disconnected
  • e-shaft sensor fouled
  • accessory belt fraying
• high end power loss (hard fuel cut)
  • Rev limit reached
• high end power loss (jerky and stumbling)
  • Ignition failure
  • fuel pressure loss
  • e-shaft sensor fouled
• high end power loss (smooth)
  • Catalytic converter clog
  • air filter clog
• low end power loss (smooth)
  • Engine compression loss
• low end power loss (stumbles)
  • Ignition failure
  • front O2 sensor failure
• revs slowly but smoothly
  • O2 sensor failure (too lean)
  • catalytic converter clog
  • air filter clog
• sudden power drop at a specific rpm
  • Intake valving actuation problem
• trouble getting to redline
  • Ignition failure
  • front O2 sensor failure
  • catalytic converter clog
  • air filter clog
  • e-shaft sensor fouled
  • fuel pressure loss
  • MAF failure

Starting the Engine

• Starter
• Battery
• Engine Compression
• Grounding Wires
• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Fuel Pump
• Fuel Injectors

Generating Power at Full Throttle

• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Air Filter
• Intake Valving
• Throttle Body
• Mass Air Flow Sensor (MAF)
• Fuel Pump
• Fuel Injectors
• Catalytic Converter (Cat)

Keeping the Engine at a Cruise

• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Intake Valving
• Throttle Body
• Mass Air Flow Sensor (MAF)
• Fuel Pump
• Fuel Injectors
• Front O2 sensor
• Catalytic Converter (Cat)

Keeping the Engine at an Idle

• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Mass Air Flow Sensor (MAF)
• Front O2 sensor
• Catalytic Converter (Cat)
• Intake Vaccum

Managing Engine Heat

• Radiator
• Thermostat
• Radiator fans
• Water Pump
• Coolant Lines
• Coolant Temp Sensor (ECT)
• Oil Coolers
• Oil Cooler Lines

Managing Exhaust Emissions

• Catalytic Converter
• Air Injection Pump
• Front O2 sensor
• Rear O2 sensor
• Coolant Temp Sensor (ECT)

Changing Gears

• Clutch Pedal Assembly
• Clutch Master Cylinder
• Clutch Slave Cylinder
• Clutch Fork
• Release Bearing (Throwout Bearing, Release Collar)
• Clutch Pressure Plate
• Clutch Disc
• Flywheel
• Pilot Bearing
• Transmission Shifter
• Transmission Syncros

Bringing the Car to a Stop

• Brake Pedal Assembly
• Brake Master Cylinder
• Brake Power Booster
• ABS Junction Block
• Brake Lines
• Brake Fluid
• Brake Calipers
• Brake Pads
• Brake Rotors

Providing Electrical Power

• Battery
• Alternator
• Grounding Cables

Thank you so much for the information, It helped me.

Were you able to find the issue and resolve the problem?

You are most welcome, Cheers