bucking and hesitation!

04speed

Member
I have an 03.5 msp and i keep having problems with bucking and hesitation in the higher rpms, the ecu is not flashed, all i have is an injen cold air intake, i just changed out the plugs to denso iridiums today and that helped a little bit, the plugs i pulled out today were bosch platinums and they had carbon on them so i dont know if that tells anyone anything, the car also bobs a little bit between 700 - 750 rpms, i dont know if this is common idle for a msp, i just recently had the wastegate waranteed so that is brand new, i have also checked all of the vaccuum lines all over the car, the car is boosting around 8 psi, if anyone has some suggestions they are very much appreciated, thanks.
 
04speed said:
I have an 03.5 msp and i keep having problems with bucking and hesitation in the higher rpms, the ecu is not flashed, all i have is an injen cold air intake, i just changed out the plugs to denso iridiums today and that helped a little bit, the plugs i pulled out today were bosch platinums and they had carbon on them so i dont know if that tells anyone anything, the car also bobs a little bit between 700 - 750 rpms, i dont know if this is common idle for a msp, i just recently had the wastegate waranteed so that is brand new, i have also checked all of the vaccuum lines all over the car, the car is boosting around 8 psi, if anyone has some suggestions they are very much appreciated, thanks.

Well im sure its just b/c your car is unflashed welcome to the wonderful world of the MSP ECU as far as the idle it could be you need to clean your EGR Valve
 
where is the egr valve located on our car, and ive heard that if i have the ecu flashed i cant run more boost, i idont really wanna run more boost but i am gonna go with an exhaust cutout in 2 weeks and im gonna gain a little more boost with that, if i have the ecu done will it make it run like s*** when i do the cutout and change to a fmic.
 
i have a cutout and used to run with fmic. what made me run like s*** for a lil while was that i wasn't recirculating my bov. so you have to make sure you get the right setup. also...as far as bogging....have you ever gotten any check engine lights? a few weeks ago i was aving crazy problems and eventually i got a CEL and it turned out my maf was ****** up. oh...and im flashed too btw.
 
the only cel that i got was for bank 1 running lean which was the problem with the waste gate, but thats all fixed now, how well did the flash fix ur hesitation and bucking problem, and what do i tell the dealership when i go in to flash it, and how long does it take to flash? how well does the car run when u just have an intake, cutout and fmic, and flash?
 
From the discription it sounds to me like you have a vac leak somewhere. Check everything again, those tiny hoses tend to crack and run fine at idle but it higher RPM under load it will show up.
 
i will go out and check those piece of s*** hoses again, lol, but as far as the flash goes what should i say when i go to the dealer and how well does it get rid of the top end hesitation?
 
04speed said:
how well does the car run when u just have an intake, cutout and fmic, and flash?
the flash was done long ago that i cant relly remember. i think it took 45 min but i could be totally off. liek i said i cant remember. my car ran fine with cutout fmic and intake once i figured out my bov issue. you can see vids of mine on videos.google.com. just search mp3architect and you can hear my setups.
 
cool thanks for all the help guys, i will keep u updated, im gonna try to get it flashed tommorrow hopefully!
 
Tell them that you have issues with hesitation and ask if their is any recals for the ECU. If they lok it up with that info they should find it.
 
If that doesn't work, try the joeP Fuel Pressure mod. Some say it doesn't work, but it did on my 03.5. When I drive the car on the track though, I have to keep boost at 7 otherwise it's not as smooth. Same with on CYN runs, at 8 or 8.5 it's much quicker but it's just not as happy and will do the bucking thing you are talking about.
 
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