still misses under load

[fixmy97gst]

My 97 gst still misses and or bucks under a load around 4000-5000 rpm , has anybody had the same problem?
I replaced the folowing, crank sensor,cam sensor,fuel fliter,thrust bearings,rebuilt fuel -injectors, and replaced the blowoff valve too ,and performed boost leak and found air leaking around the throttle body gaskets..that was repaired too set the plug gap to your recomended settings..could it be the ECU or coil pak or is it the rev limter...also after having the injetors rebuilt, the car has a hard time starting when warm about 6 revolutions to start...It's a awesome car but I'm running out of money and paitence...please help this dsmer...

Note: this car is compleatly stock...no mods

 

[meh]

check your plugs, when was the last time you replaced them?

 

[BISHILVR]

plug wires my friend..........

 

[FutureGSXOwner]

Yep..I had the SAME bucking/fuel cut problem under WOT and replaced my NGK 6's with the 7's and the problem has gone away completely. I went from having to run 12psi to now being able to run 20psi again with no bucking/high egt's whatsoever.

 

[fixmy97gst]

Yep..I had the SAME bucking/fuel cut problem under WOT and replaced my NGK 6's with the 7's and the problem has gone away completely. I went from having to run 12psi to now being able to run 20psi again with no bucking/high egt's whatsoever.

Guy's I've had replaced the the plug wires with NGK (blue wires) what is the difference between NGK 6's or 7's..I think something else could be the problem...Don't know???

 

[Pj97GST]

are you still running the factory plugs? If so, get rid of em.. you want either NGK BP7ES's or BP6ES's (non-resistor) other than that check what I mentioned in the PM to you.

 

[Mitsu725]

I had the same problem after i ran someone, it just starting missing like hell, went home parked her, took out the plugs the next day, and found out they were gapped at a .40 or some ridiculous huge number so i gapped them to a 28 and she ran perfect has been fine ever since, i sued br6es, every1 says i should use like an iridium or something but i use cheap 1.49 plugs and my car runs great, i was told to get bpr6es instead of br6es but they were out and the P i was told only stands for projected tip, and i dont have that but so far so good. Well see what happens i been on them for 3 months now.

 

[fixmy97gst]

Wel now I've replaced the coils and the same friggen miss and bucking still exisit durning hard acceleration...HELP!! this car is really starting to suck :thumbdown

 

[ZmanIV]

think i have the same problem
seems to be intermittent and happens from 2400 to 3000 rpm after that im ok
I think it is either a fuel delivery problem or a boost leak. I am going to purchase the parts to make a boost leak tester along with purchasing a boost guage hope to fix this soon.
My gst is stock 1998 no mods bought it in may this year. dont know the previous owner or if there was any other problems. other than that i love it handles great and lots more fun than my previous car.
let me know what you find out.

 

[cuong1106]

what kind of plugs are you running? if you are running bosch platium then take those out and throw them away. put some ngks in there. go to a oreily and they should have some.

 

[AWDPetmitsu]

Have you checked the throttle position sensor?

 

[ZmanIV]

new ngk plugs were installed about 2 months ago and havent checked the tps yet. this morning on the way into work it was a rocket no problems at all lots of power. the problem seems to be just after it starts to warm up temp guage will have just gotten into the optimum range and then the problems start. after about 5 minutes of crusing on the highway problems go away.

 

[me612]

inspect the wires thuroughly. check the long rubber piece that goes into the plug well for any small pinholes. If there are any little holes. Also make sure there is no moisture build up at all in there. Either of those will cause arcing inside the well and cause missfiring.

 

[Coldandafraid]

Another vote for wires here. I had same problem so I replaced everything, including wires... nothing fixed it. Then, I decide to resistance test the USED wires I had put in... yeah, one was bad. New wires, problem gone.

 

[ZmanIV]

checked the wires for burn holes and moisture in the well none there
ill check resistance.
are the parameters in the book ok or should i be verifying to another spec

 

[me612]

I know this may sound like I'm beating a dead horse here, but I know there's a ton of other DSMers in Diago. Find one of em and swap out wires with them. See if his car now bucks with your wires, and see if yours runs fine with his. Really sounds like wires man. Also could be too wide of a gap on your plugs in conjuction with too much psi.

 

[Sic95gst]

Guy's I've had replaced the the plug wires with NGK (blue wires) what is the difference between NGK 6's or 7's..I think something else could be the problem...Don't know???

My car did the same thing so i went and got me some BPR7es and the car is running so great. i have 6 more plugs i'm not using pm me if your interested. I had to buy a damn box because they were special order.

 

[fixmy97gst]

I have replaced crank sensor,cam sensor,fuel filter,air filter,ngk plugs 6's, new ngk blue wires and have inspected the plugs which'd look good still the same dam'm bucking under load , I can get it up to 5000 lightly winding it out but the moment I give it gas the bucking begins...but this time I got an CEL took it to my friend which has a OBDII it said #4 cylinder misfire....hmmm don't know what to think...might just get rid of this dam'm car and go back to a 240sx or just keep driving my trusty 85 toy celica gts....

 

[me612]

OK so you know where the problem is. Start troubleshooting cylinder 4, or give it to someone who will if you want to give up. If it were me, first thing I would do is replace the plug and wire on that cylinder and see what happens. I know you've said you replaced all this, but who knows, you coulda gotten a bum wire or plug. You also say this happened right after you got your injectors rebuilt. Well maybe try swapping in a buddies injectors for a couple days and see if it goes away.

 

[fixmy97gst]

OK so you know where the problem is. Start troubleshooting cylinder 4, or give it to someone who will if you want to give up. If it were me, first thing I would do is replace the plug and wire on that cylinder and see what happens. I know you've said you replaced all this, but who knows, you coulda gotten a bum wire or plug. You also say this happened right after you got your injectors rebuilt. Well maybe try swapping in a buddies injectors for a couple days and see if it goes away.

It was misfiring before the injectors got rebuilt, I've replace the wires twice durning 15000 miles and the plugs to and to top it off mitsu can't even tell me whats wrong with the car...and they are the one's who built it! and go to training on that car as well! I just hope that the same problems don't crop up on the evo!

 

[EclipseGST-95]

mine is doing the sammmme thing....for a while i thought maybe the cat was clogged....but my pops said he thinks its injectors...we replaced the spark plugs with the ngk bpr 6es sparkplugs...it idled a lil better i had iridium's in there b4 pulled them out n they looked fine....when im at WOT....my boost will shoot up to 15 psi and drop down to 10...still not building power...my car is just accellerating sooo discustingly slow...and it shakes the entire time...the exhaust sounds like a modded sti spuddering throughout the whole rpm range....im takin it to mitsu to see what they say hopefully its something simple...it ran fine last night but i started it up this morning n drove it to practice and it ran like poop...dsm's suck when they feel like they're runnin on 2 cylinders... :thumbdown ...ill let u guys kno if i find out or ever get the problem fixed oohh by the way while its shaking at WOT...the air fuel is stayin in rich but all over the place on the rich side...changes at the rate of the car shaking i hope its nothin serious

 

[PlayerZ]

ok, heres another one. i got a 92 galant vr4. we had a idle problem, fixed that (thanks to terry's troubleshooting) we pulled the emissions, the vpc, and put the stock maf back on and changed the coil, fpr, and plugs and wires. but now the car bucks at about 4500 only under hard acceleration. any guess's

 

[EclipseGST-95]

my problem was solved....key...sp wires

 

[gsxtacy]

You can change actual plugs all day and have the same problem,...tell us what these new plugs are gapped to.

Just because your ole' chevy pickup has HEI ignition and the plugs on it are gapped to .050 doesn't mean thats the best gap for everything.

Its says right on the underside of the hood. .028"-.032" spark plug gap.

If your modded at all ( over 15 psi ) change the gap to .026"

I can't assess a problem with a engine 10 states away unless you give specific symptoms, and all the specifications of everything that HAS/HAS NOT been done.

Tell me what YOUR plug gap is first, all you need is a feeler gauge.

gsxtacy

 

[AWDTALON3000]

I have the same problem, the car hesistates under hard acceleration. I have the right plugs and cap. I am just wondering how long do plug wires usually last. I put some 8.5mm wires in 3 years ago, is it time for new ones??