r33 gtst jerks while accelerating in 4th and 5th gear..HELP!

[tcplaya3]

ok so couple weeks ago my r33 gtst would completely shut off around 4-5 rpm in 4th gear. 1,2,3 are smooth all the way through. if i dont accelerate too hard in 4th, i can pull through fairly but around 5-6rpm the car jerks and wont let me accelerate. then i shift into 5th and same thing happens, but this time during the lower rpms (2-3.5).

We changed the spark plugs, and now the car doesnt randomly shut off. took care of that..

as for the restriction/jerk during higher rpms in 4th and right away in 5th, the problem is still there. The car wont accelerate and jerks and just looses power when i press the gas (like a flat spot). I cant even go fast enough to keep up with the cars on the highway.

ECU is tuned to 100 octane, but with 110 race gas same thing happens..

A stock ecu is on its way..will try that.

Buddy said it could be a boost leak under full pressure..?

Guy before me put 3" mid pipe with huge exhaust, but the front/down pipe is stock..which restricts airflow in the beginning. ill order a 3" downpipe soon..

everything else is stock except for intake and grounding kit.

Please help me out!!!

EDIT: PROBLEM SOLVED!!!!

[BrianV8]

hmm thats an interesting one, check the ecu for codes. Ecu in a lot of ways can help you a lot in diagnostic

[tcplaya3]

yeah its weird how i can pull smooth/strong all the way through the first 3 gears, but end of 4th and right away in 5th this problem occurs.

Im going to plug a stock ecu in when it arrives and check it out..

[BrianV8]

ya give that a try for sure, odd issue. Make sure you make a post see what the problem was

[tcplaya3]

ill keep everyone updated.

if anyone has any other suggestions please let me know! thanks

[Skym]

What ECU.??? Retuned stock ECU???

[tcplaya3]

to tell you the truth i have no idea..no label on the ECU..but its tuned to 100 octane. My stock oem ECU should be here soon, original settings. ill give that a try.

[geng]

i had this issue i replaced my injectors and my MAF and it got rid of the same issue. also it was masking the issue as well i had dead coilpacks and i ended up replacing them as well. basically. its not the tune. it might possibly be a fuel cut. but it wouldn't be that bad.

[Chewy]

I'd check that boost leak, also can be a maf grounding issue.

[DreadedFist]

mine did this when my spark plug gap was to big. gapped down to about .7 and its all better. its amazing what about .3mm worth of gap will do to an engine.

If you already have a good gap, then I got nothin.

[geng]

boost leak wouldnt cause it to jerk. nor would it only event just 4th and 5th. maf is the most likly suspect in all 3-5 cases ive herd of this every single one has been the MAF

[tcplaya3]

i had this issue i replaced my injectors and my MAF and it got rid of the same issue. also it was masking the issue as well i had dead coilpacks and i ended up replacing them as well. basically. its not the tune. it might possibly be a fuel cut. but it wouldn't be that bad.

actually it is a fuel cut. it doesnt really jerk (i didnt know how to word it) but when i hit the gas in those gears the fuel cuts right off..and the car doesnt accelerate. thanks for you help man

[tcplaya3]

boost leak wouldnt cause it to jerk. nor would it only event just 4th and 5th. maf is the most likly suspect in all 3-5 cases ive herd of this every single one has been the MAF

yeah its more of a fuel cut after a small one-time jerk. cant be boost leak if the first three gears are fine..thanks for your help

[geng]

ohhh ok. sorry hmm. than yeah if it just hits fuel cut it might be a tune issue. also check all your vaccum lines i remember on my buddys 2jz one of his waste gate lines was pinched and it caused a fuel cut. food for thought.

[tcplaya3]

mine did this when my spark plug gap was to big. gapped down to about .7 and its all better. its amazing what about .3mm worth of gap will do to an engine.

If you already have a good gap, then I got nothin.

they are gapped to .8
that solved the car shutting off over 50mph issue