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

[tcplaya3]

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.

fuel cuts only happen under full pressure/higher gears? i will check all the hoses, and MAF.

[tcplaya3]

i took it out again. so around 4.5rpm in 4th it feels like a fuel cut, but around 2.5rpm in 5th it jutters/vibrates/jerks/ whatever..

im waiting for the stock ecu.

[tcplaya3]

ok the stock ecu arrived, replaced it with the other one. car drives smooth, but the same jutter in 4th and 5th occurs.

in 4th it happens at 3.5rpm
in 5th at 2.5rpm

it jerks once and stops accelerating--no power.

ecu is out of the way, now what? MAF?

[DreadedFist]

Well, there is way more load on the engine in higher gears. Could it be a sign of a weakening fuel pump? Less load = fuel pump isn't pushed as hard. Is it still stock?

[tcplaya3]

yeah its stock, im pretty sure it is.

just took it out today...in 4th at 3.5rpm exact the car went "drrrrrrrrrrrrr" and lost power..rpm dropped to 0. steering got heavy. then i down shifted to 3rd, gave it gas and it started again. it usually makes that "drrrrrr" sound but this time it kinda shut off..i think because i kept it at 3.5rpm for too long..

i have an appointment tomorrow they will wire it up and check out the readings..
then ill check the maf and fuel pump. how can you tell if the fuel pump is going bad?

everyone thanks for your help, and if anyone else has any ideas please let me know.

[DreadedFist]

Honestly, if the pump looks original, change it. They're pretty old. Use a walbro 255 or something similar.

[tcplaya3]

probem solved!!

[DreadedFist]

probem solved!!

woah woah woah, you have to tell us what the problem was!!!!!!!!!!!!111

Otherwise the next guy with the same problem has nothing to go on

Was it the fuel pump afterall?

[tcplaya3]

no it wasnt the fuel pump or maf etc..!!

couple weeks ago i posted a thread about my speedo not working. well i got my new speedo in the mail. my original one's green board was cracked and the needle stayed at zero while driving.

i replaced the speedo today, tried going over 3.5rpm and it was smooth! all gears are smooth!

my theory- the bad speedo was sending retarded signals to the ecu..hitting the limiter or something weird or whatever it was..the cracked speedo was the problem!

[Skym]

When there's 0 km/h, stock ECU engages the safety revlimiter.