Engine Jerking at over 5000-5500rpm

[douglas218hk]

Hello all, I don't know why, my engine is jerking at about 5000 to 6000rpm
moreover, it has a hesitation when step on the pedal from stop or from a braking to stop before.

I haven't encountered this problem before.

I am using Denso IR20 spark plug.
K&N air filter for original air box.
S-type exhaust pipe.
15" wheel rims with 195/55/15 tires
No turbo or super charger.

I have replaced all sensor in it except the O2 one but nothing help.. vv
Any one can help me?!
Thx for your advance!

 

[Ryoga28]

No turbo or super charger.

So do you have a MSP or protege???

 

[douglas218hk]

So do you have a MSP or protege???

Yes, it's a protege, but we call mazda 323 1500cc here.
It is using a ZL series engine.

Am I wrong?

 

[Ryoga28]

You're not wrong about it being a protege, but your post was in the mazdaspeed protege section which made me assume you had a MSP (factory turbo'd). You may want to post your thread in the N/A section or request a Mod to move this one for you.

 

[douglas218hk]

You're not wrong about it being a protege, but your post was in the mazdaspeed protege section which made me assume you had a MSP (factory turbo'd). You may want to post your thread in the N/A section or request a Mod to move this one for you.

Oh, I see.. I am sorry for that!

 

[redlightgo]

Had the same problem once. It turned out to be the wastegate acuator. Replaced after a s*** load of hassle by warrantee.

 

[douglas218hk]

Had the same problem once. It turned out to be the wastegate acuator. Replaced after a s*** load of hassle by warrantee.

Where is the wastegate acuator?
Is that a valve which control how much fuel return back to the fuel tank?

 

[Matrix]

Where is the wastegate acuator?
Is that a valve which control how much fuel return back to the fuel tank?

It's function on the turbo cars to regulate boost. Not applicable to your naturally-aspirated car. Don't worry about it.

If I were you, the first thing I'd do is check all the plugs and replace the spark plug wires.

 

[mspdfreak]

Could be a bad IAC valve. About $600 to get replaced at the dealer.

 

[redlightgo]

yah didn't check to see what car you have, but I exp. surging much like you described on my Turbo protege. Wastgate opens and closes to allow the turbo to spool or release pressure. Mine would close up @ 4.5k and then slam open @ 5.5k rpms