Still stuttering

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03 MSP Blue
I still have an issue with hesitation under acceleration. After 3k it cuts power. Around 4500, the engine is pulsing kind of like a miss. I've replaced the wastgate diaphragm, and got corksport intercooler pipes. I thought the bypass valve might be leaking (I know this sounds weird) I put super glue around the seam. The only other "mod" was replacing the air box with a k&n cone filter. No vacuum leaks that I can find and I don't know if it's been reflashed and don't know how to tell. My next step was to see if the intercooler is leaking. Outside of that or the fuel cut, I'm at a loss. Any suggestions?
 
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MazdaSpeed protege (yellow)
The only thing I can think of if it doesn't have a check engine light on is the Tuning. The intake being changed could be throwing off the Air/Fuel just enough. these cars have a kinda crappy tune. split second sells a programmer that's got a base map downloaded onto it out the box thats suppose to make these cars run alot better.
 
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03 MSP Blue
I'll check the maf and post the results. I've replaced the coils a couple of years ago. Maybe time to test those too.
 

323

(u_u) ...zZzZzzz
Moderator
check your vtcs and vics solenoids on top of your intake manifold. they're the two with the green and white plugs. if you hook up the terminals of the solenoid to a 9v battery, it should click. if it doesn't, replace it. my vics solenoid was dead and it every time i got up to about 4k rpm, it would stutter but never threw a code.
 
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03 MSP Blue
Bypassed vics by removing circlip that holds shaft of diaphragm to shaft that turns valves and turned to open. Bypassed vtcs by replacing vacuum line to diaphragm with cap. Car absolutely hates full throttle.
 
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2003 Mazdaspeed Protege, 2008 Mazda 3 Hatchback, 1984 RX7 GSL-SE
Still sounds like an ignition problem to me. My parts store coils last 2-3 years before they start to fail. It's not always catastrophic, sometimes it just starts missing under load. I'd check wires and plugs too.

It's worth buying another coil and swapping it in to see if you fix the issue. If not, you at least have another coil in the trunk for the next time a coil dies
 
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97camaroSS e30 318is Spicy #1348
Im getting that same stutter at the same RPM. Im stock with 115k on the clock. I just got a code for the VIC
 
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Yellow MSP
I would check all the stuff that costs zero dollars first. Like double checking that all hose/intercooler clamps are tight, no hard or rotting vacuum hoses. An intercooler that does not have a tight seal, with a good clamp, will give you issue boosting, and going above 3000rpm can make the car buck. I just had this issue when removing all the intercooler pipes to change a bursted water return hose that is buried under everything.
 
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