GTR 33 running rough, kinda chugging

[coach]

Hey, I started my gtr last week and it was running great. This morning I start it up and it is running like crap.
It is running rough, kinda chugging.

I had this happen once before when I drove away from a shop. I went back to the shop, they pulled it back inside and 20 minutes later it rolled out running great again. They told me it was a fuse, problem is they never told me which fuse.

Now I have the same problem and can't seem to fix it myself. I have checked the fuses and all appear to be fine.

Does anyone have any ideas ? Or has anyone has this problem in the past ?

[speedfreak]

No fuse would cause that symptom, they were just blowing you off.
If the engine is rough running you ca figure
out which cylinder by unplugging an ignition coil if it changes the way it shakes then that's a good cylinder.
If it doesn't change that's your suspect cylinder.
Now you need to swap coils (check plugs while you have those coils off) and see if the coil that was on the bad cylinder follows to the next position so if it does them you have a bad coil.
Start with this process.

If it doesn't and the same cylinder is bad you need to check injectors.

[krystalized_jdm]

Hard to pinpoint, I had a similiar issue. Turns out I had a bad coilpack, replaced it and she's good.

Pretty much everything speedfreak said

Since you're pulling coilpacks, I'd recommend new plugs. 30 bucks for peace of mind is nothing.

[Skym]

Probably running on 5 cylinders. But can get stuttering (similar to coilpack failure) if intake hose clamps on MAF's x2 are not tight enough, or there's intake leak (crack) just after MAF's on stock rubber intake piping. Sometimes crack is just under intake hose clamp (cuts into rubber intake piping if tightened too much).

The way speedfreak mentioned, or test them on bench with multimeter or coilpack testing machine, as the failed coilpacks output less voltage. I tested my cars coilpacks on bench via coilpack testing machine and the two weakest coilpacks had lower output with voltage.

Also failed coilpacks have grey tracking marks on both sides of coilpack and if pull the sparkplugs, the tip on cylinder that's not firing is black (what happened on my car).

Coilpacks usually fail due to incorrect sparkplugs (sparkplug gap or heatrange) that cause missing at higher rpm (common for 2x coilpacks to fail when this happens). Should be gapped down to 0.8mm.

[coach]

Can I do harm to the motor if I drive it to a shop like it is ?

It's not the repair, it's the trouble shooting that I would take it to a shop for

[speedfreak]

Yes

If a coil is not firing but the injector is still spraying then fuel gets into the oil and thins it out causing oil to wash out then bearings will have no protection.
Also cylinder walls wash out and piston ring can wear into the walls causing scratches.

[coach]

flatbed it is then

[speedfreak]

I wouldn't take it to that same shop.

Where are you?
Maybe check on some other shops that are more familiar with your car.

[coach]

LOL, I am in Winnipeg. So I only have 2 options.....lol. A place called Speedfactor here in Winterpeg is were I will take it. The oather shop is actually a very good shop as well, and they did get my car running great again. Still not sold on the coilpaks, but it makes sense. The weather here is not good enough to work on a car outside just yet.

[hp44incgtr]

its most likely yo coil or coil pack wire loom the wire are old on the outside look good but i bet if you open them up some parts are prob green, i replace the coil wire loom and coil to fix my problem and if its still running the same check the o2s...

[Skym]

Can I do harm to the motor if I drive it to a shop like it is ?

It's not the repair, it's the trouble shooting that I would take it to a shop for

Yes, like speedfreak mentioned. The coilpack still fires on that cylinder, but spark is not strong enough, as charge is leaking out the seam that joins two parts of coilpack together and onto coilpack mounting bracket, etc. Some dip coilpacks in resin to seal the crack (temporary fix that works).

I drived my car to tuner shop to get coilpack changed (they had coilpacks in stock). Then changed oil, filter afterwards and engine ran ok and has for many years afterwards. Should replace all 6 coilpacks every 100,000km (same time as they recommend to change sparkplugs) if used on road, alot less if used for drag (some do it after each run on 1000hp+ engines, as can afford to do so), racetrack.