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TOO broke MK3
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841 Posts
Discussion Starter #1
ok first time its was little skip...

so i thought about it could iether be fuel cut or tires...

-but found what fuel cut eally is so thats ruled out...

-now the tires... i just got some used tires but lots of threads left... and so its not that..

-someone sudgested that the car is misfiring... so i change the plugs(wich cost me some extra time b/c chanpion plugs broke off)(see my other thread)i install new plugs so thats rulled out...

now open for anyidead why my car studder or sort of alot of skip in away...

to be more specific on the problem...
-when NOT in boost the car drives fine...

but when i hit boost the car just studder... it gain some speed but not like b4 when you can feel you head being pulled back...it still read 10 psi on boost guage...

my mods are
-BIC 3" dp
-modifide intake
-turbo shimmed to 10 psi...

anyideas?
 

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TOO broke MK3
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841 Posts
Discussion Starter #4
Reign_Maker said:
plugs... what kind are they?

Check for any vacuum leaks, or boost spikes...
the car was acting the same way b4 i chang ethe plugs so i dont think its it..

the plugs are bosh platinum... i was ganna get ngk but i have to order it... and i need the car running by tomorow... and i dont think it needs to be gap... am i suppose to gap it? i never do :lol:

the boost gauge read 20 vacume at idle and isnt that normal?

also whats a boost spikes?
 

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1991 1JZ
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1,157 Posts
drjonez said:
did you gap the plugs? $5 sez no....
my car started doing the same thing when i raised the boost, the rebuilt motor does it as well. at first i thought it was a clogged fuel filter, changed that out and the car still does it.

AND now that i think about it, i didnt check the gap on the plugs.
 

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My car does this on the highway when in 4th or 5th and start going into boost. I always just assume the tires can't handle my supremely stock power, and lose tractioN!!!
 

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slow.
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Twin_turbo_mk3 said:
the car was acting the same way b4 i chang ethe plugs so i dont think its it..

the plugs are bosh platinum... i was ganna get ngk but i have to order it... and i need the car running by tomorow... and i dont think it needs to be gap... am i suppose to gap it? i never do :lol:

the boost gauge read 20 vacume at idle and isnt that normal?

also whats a boost spikes?

ugh! bosch plugs are garbage. at least for the 7m, that is. As well as champion plugs. And no i'm not basing this off of rumor, i've found it out through trial and error first hand. NGK's or autolites are the way to go. denso's work as well.
 

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Slowly but Surely
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my car still does that up til this day. I thought it was the plugs but they were pregapped (NGK). I think it might be the fuel filter. IIRC, NeverNz had the same problem but I don't know if he ever got around to fixing it.
 

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i have the problem also but only when it starts to hit peak boost. i thought it may have been the flywheel because it wasnt correctly surfaced before installed.
 

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1991 1JZ
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1,157 Posts
*BLacK SuPrA GTE* said:
my car still does that up til this day. I thought it was the plugs but they were pregapped (NGK). I think it might be the fuel filter. IIRC, NeverNz had the same problem but I don't know if he ever got around to fixing it.
i thought it was the fuel filter in my car aswell, but i changed that and it didnt help.

im gonna check the gap on my plugs, then if that dosnt solve the problem i suppose ill have to try harder to track down some vacuum leaks.

my car usually dosnt idle very well either, i think ill narrow it down to the spark plugs, or a vacuum leak.

...well, let me replace the freeze out plug that blew out while i was driving first... :rolleyes:
 

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Blackzilla
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1,579 Posts
Enslaved87 said:
ugh! bosch plugs are garbage. at least for the 7m, that is. As well as champion plugs. And no i'm not basing this off of rumor, i've found it out through trial and error first hand. NGK's or autolites are the way to go. denso's work as well.
Edit: oh wait you said while on boost. Check for leaks from the AFM to the TB.

I agree.

Check your timing as well. My car was doing tha and I found out my timing was like -15 somehow. Bert and I had a fun time with the cps before we got it fixed.

BTW if you can't fix it I'll take that downpipe off your hands.
 

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...heading for 500+ RWHP
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467 Posts
My car is doing the same thing...... :rolleyes: New plugs properly gapped didn't fix it. If you've checked the plugs and under boost the car stutters, hesitates, or has a miss then the problem (IMHO) is only one of two things....a boost leak...or a fuel issue. I working on fixing the problem of a small boost leak right now....(getting 10-11 psi with no aftermarket boost control and hitting fuel cut) If my new hardpipes and intercooler don't fix it....I'll move on to fuel. Just more excuses for me to put new parts on the car! :bigthumb:


Remember...a boost leak dosen't have to be a noticable hole or rip. It can be a pin prick size hole or rip that expands under boost and still cause problems.
 

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TOO broke MK3
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841 Posts
Discussion Starter #17
ridah said:
Edit: oh wait you said while on boost. Check for leaks from the AFM to the TB.

I agree.

Check your timing as well. My car was doing tha and I found out my timing was like -15 somehow. Bert and I had a fun time with the cps before we got it fixed.

BTW if you can't fix it I'll take that downpipe off your hands.
i dont think ill be selling the dp... unless i get really desperate for money... the 3" dp is the only thing thats giving my car power lol...




turboa7mgte said:
Sounds like you are leaning out.... Bad 02?
Boost leak?
huh i though that when you have a bad 02 you will be running RICH... thats why some people disconnect them in hopes to get better throtle responce... or did i get that all rong? :dunno:


jin-chuu said:
i have the problem also but only when it starts to hit peak boost. i thought it may have been the flywheel because it wasnt correctly surfaced before installed.
ill rule out flywheel or any clutch stuff... mines abour maybe 5k or 8-10k on it (not sure lol) ... baught both NEW


Lord Mike said:
My car does this on the highway when in 4th or 5th and start going into boost. I always just assume the tires can't handle my supremely stock power, and lose tractioN!!!
same thinking here... but then its gotten worse... :( couldt it be the deferential? although i doubt it...



ok so far heres what i need to check...
-proper spark plug gap...um what is it?
-boost leack betwin or from afm to trotle body...
-timing-what tools will i need for his job?
-fuel filter(running lean)
 

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I've got the same problem and have had it for quite some time now, was gonna change my cps this weekend but instead I changed a knock sensor and finally put on the t-bolt clamps that have been sitting in my room for months. I think its either my cps, timing, or plugs leaning towards cps right now.
 

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slow.
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1,016 Posts
when it misfires... does it sound like popcorn? or does it just cut out... if it feels like your being pulled backwards under boost it very well could be timming. Go buy a timming light and hook it up. It should be set to 12 degrees.
 

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I had the same problem for a long time. I spent hundreds of dollars for shops to look at it. I checked codes over and over and got nothing. I took it to someone who had a good knowledge of the 7MGTE engine and he said sometimes the knock sensor goes bad but never shows the code. He replaced one of the knock sensors and that fixed it.
 
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