bryan767

iTrader: (6)

recently ran into a few problems with my sc300 1jzgte:

the main concern is that it bogs in the 2-3k rpm only.. like it hangs there for a few moments then itll accelerate past the 3k rpm point. at which time ill hear a pop,pop,POW.. (itll also start to shutter sometimes, and try to learch forward) and then ill accelerate throughout the rest of the gear. HOWEVER if i accelerate slowly, as if a cop were behind you, i dont have any bogging throughout the power band.. say anything past 25% throttle and itll bog and miss on occasion.

i recently replaced my clips on the coil packs which made alot of the missing sounds go away (i had a low, very fast, thumping noise at the same time as the louder pow pow BANG).. but this one purists!

mods:
stock 1jzgte
fmic
greddy type s
12v fuel pump mod
3" cat back
relocated battery

im thinking its either the coilpacks, fuel filter, fuel pump, tps, map or fpr.. maybe even of a boost leak?

what do you guys think it is? i thought about putting another fuel pump in but a stock 1jz shouldnt need that right?

Slo300

being big on dsm's i don't know how much this will help you but i know the problem. A friend of mine had a bad AFPR and his would bog and hiccup just like yours. However if you smoothly got into the throttle it acted fine. He went over all spark issues and couldn't figure it out.

I'm assuming this is your fuel pump taking a dump!

After about a week he found a vacuum line had come undone from the AFPR and the car run perfect after which.

- However if it's a boost leak, you would hear it out of car and it would be alot harder to make boost. Make a boost leak tester and post results. It's never a bad idea to check!

bryan767

iTrader: (6)

thats exactly what i was thinking man. i think im going to replace my afpr..

hurray for getting a new job

shlounek

iTrader: (1)

Had a similar problem, sometimes it is bad gas.

drove the car till it was empty filled up premium added Lucas to fuel and repeated process, now it revs all the way through no problems.

It is worth a try.

bryan767

iTrader: (6)

^^ill give it a try, i just moved to a new town and it started when i put 92 in since theres only one gas station with 93 out here..

FutureSC

iTrader: (1)

What kind of spark plugs do you have in there? Possibly the wrong heat range?

bryan767

iTrader: (6)

ngk iridiums gaped at .27.. i tried from .30 to .25

and i think its my FPR.. i ran a few vacuum lines off it (heat and boost gauge) and im thinking it cant keep up with all of it? maybe idk, i figured a vacuum was a vacuum

FutureSC

iTrader: (1)

I wouldn't think it is a vacuum because it's not happening at idle at all is it? But replacing the afpr isn't a bad idea

Could be the fuel pump simply dying out on you in that range too

BostonSC4

iTrader: (2)

Best of luck man. Does a 1j have a MAF? Mine sc4 did these symptoms when that went bad.

bryan767

iTrader: (6)

nah its a map.

and yeah ill be replacing a few things to see if thats it. what kind of fuel pump should i get?

edit: did some looking, im goin to try and undo my 12v mod.. i read a few threads with people have the same problems as me.. and its the 12v mod. im thinking it has something to do with the wiring, now i know i wired it right.. because my car runs, but IIRC this problem started after i did this mod (my car was down for a few weeks while i was doing mods to it.. and i dont really remember.. its been like this for awhile now since the 12v mod was the first mod i did)