RPM drops suddenly
 

Hi, i have little broplem, it will happen sometimes. (4 times at the moment, in past 1,5 year) RPM drops suddenly when redlining. it drops like to 3000-4000 rpm.
Hope some one could help me whats up, hope engine is health :sad:

I have owned the car since -08 summer, now driven by 88 000km = 53 000miles.
RX-8 R32 (high power), with mods (on signature) but first time issue came out when car was "original" without mods.
All maintance are made in right time and recalls done.
Every 10 000km = 6000miles, oils have chanced and filter. Plugs and wires are new also, the coils are new, but it did not helped.

sry for my bad english.

Valtteri from Finland

If you could describe the behavior a little bit more precise maybe somebody can give you better hints, but with just this information here comes the possible cause list:

• Vacuum leakage
• Air leakage from intake-air system
• Air cleaner restriction
• Air suction at intake-air system (between MAF sensor and intake ports)
• Throttle body malfunction
• Improper SSV operation
• Improper APV operation*
• Improper VDI operation
• Improper operation of drive-by-wire control system (abnormal accelerator position and TP signals to PCM)
• Drive-by-wire control system in fail-safe function (abnormal accelerator position and TP signals to PCM)
• Poor fuel quality
• Inadequate fuel pressure
• Pressure regulator (integrated in fuel pump unit)
• Fuel pump mechanical malfunction
• Fuel line restriction or clogging
• Fuel injector improper operation
• Fuel injector malfunction (leakage, clogging, improper injection amount)
• Intermittent open or short in fuel pump related circuit
• Restriction in exhaust system
• Leakage or blockage exhaust manifold
• Purge solenoid valve malfunction (stuck open)
• Erratic signal from eccentric shaft position sensor

• Improper ignition timing control (abnormal ECT, IAT, MAF and knock sensor signals to PCM)
• Improper fuel injection control (abnormal MAF, ECT, front/rear HO2S and knock sensor signals to PCM)
• MAF sensor improper installation
• Spark leakage from high-tension leads
• Spark plug malfunction
• Incorrect spark plug heat range
• Engine overheating
• Low engine compression

– Engine internal malfunction
– Abnormal engine oil condition (viscosity, deterioration)
– Low oil pressure
– Excessive fuel pressure
– Air mixed in oil line
– Metering oil pump malfunction

• Leakage or clogged in oil pipe
• Leakage or clogged in oil nozzle

• Metering oil pump malfunction
• Improper metering oil pump control operation
• Improper A/C system operation
• Brake dragging
• Low tire pressure
• AT malfunction (AT)
• Improper operation of torque converter clutch control (AT)
• Clutch malfunction (MT)

When rpm drops its like lack of power, like im hitting the pedal on the floor but feels like i take foot off the pedal for 2s. This have happend now several times.. in past 1,5y.. Normally everything is fine. Engine sounds healthy, only sound what it makes is when idling, but when pushing the clutch it stops.

Im using the highest octane fuel what i can get in Finland Shell V-Power its 99E, if thats not available 98 then, normally cars use 95 or 98 octane.

Engine temperature is never high, always below the center.

Oil pressure is usually about in the middle never higher.

Yeah and i have the strange cream in oilstick, but i think thats normal, couse in all rx8 in finland (cold weather) has it and what i have read in this forum, its not that bad.

Brakes are new and not bracking also tire pressure is ok.

And the car is manual, all gears go well. only 2:nd cear is broblem when car is cold, its harder than others, but not making any sound, and when warm no broplem.

I think i'll need to to compression test to check.. Hope engine is not going to die.. Rebuilds in finland costs a lot, and very few people can do it. Or ill try DIY with my mechanic friend.

fuel injectors