Hey guys! Just looking for a little help or advice.

Recently I decided to do some spirited driving and got on it, wide open throttle (WOT), in second gear and the car was running fine til about 4k. At 4k the motor felt like it stopped or something for a split second then continued on un interrupted. Prior to this happening I had my rear O2 sensor go out on me which I don't think would be the cause.

Anyhow, I changed out my O2 sensor today for kicks and the car still stutters. I searched around EvoM a little and found mentions of clutch going out, fuel cut, and boost cut. I can't see why it would be fuel or boost cut cause no new mods have been added to the vehicle in a while. Im really hopeing its not the clutch because it was recently replaced 6k miles ago and I haven't launched once on the new clutch. Plus if the clutch was going out wouldn't I see my RPMs spike up when the car jerked instead of pausing or falling?

Im kind of clueless and still a newb so any ideas or recommendations for trouble shooting this issue would be greatly appreciated.

Thanks in advance

Mods Include;
Test Pipe
K&N Intake w/ MAF attached
Downpipe
O2 Housing
Walbro 255
Not Tuned Yet...

I know, I know not tuning is my first mistake

 

blow off valve hooked up backwards or a leak somewhere will cause this jerkiness

 

the intake could be causing u to hit boost cut or fuel cut

 

Not tuned yet? Would some good knock cause stuttering? Why would the rear o2 go out? I know sometimes they bite it, but you could be running too rich?

-Will

 

Still running the factory DV which is on correctly but I will definitely check for leaks. Any suggested starting points?

Definitely not tuned yet but was actually planning on it this May which is now on hold till I get this straightened out ... The rear O2 had a wire get pinched off by the chassis cause of the O2 defouler. I know newb mistake.

Thanks for the advice so far guys. It looks as though Ill start around the intake area and work my way back looking for leaks. Any others please chime in as well.

 

check your sparkplugs?
running too rich or massive knocks can cause similar sympton (pull timings).
It's happening at peak boost so more likely those above.
definitely not fuel cut because you'll know it.

 

Would a plug issue cause the jerkyness cause I didn't even think about the plugs... Im at around 60k on factory plugs so it may be time ...

 

Yeah. It could be a simple missfire or ignition break up that's causing the "jerkyness".

 

Well crossing my fingers and hoping its as simple as that.

 

sounds like a boost cut. get it tuned. all those upgrades without a tune will really make you hit your boost cut most of all when the weather is cold.

 

60k on factory plugs

wowzers

 

definately agree with this...


i change out the plugs every 6000 miles... if i feel kind, i will change them every oil change...

 

oem plug is iridium so it could last much longer than copper. Changing plug every 6000 miles is extreme.

 

definitely seams like an ignition missfire. Check the plugs and condition of the wires. Be carefull when you take the plug wires off, you only wanna pull on the rubber boot not the actual wire itself.

 

i agree on ignition too.
check the plugs, but also check the wires and coil packs. I had an annoying breakup in my Supra for a while and finally inspected the coilpacks one by one and found tiny hairline cracks in the tips. was just enuff for spark to jump and cause the car to go crazy in boost.