stuttering at full throttle 3.1 V6

[michi]

Hey, ive got a new problem here... when i do full throttle it has a short stuttering and i noticed on autobahn at like 80miles it smokes out some black smoke of the exhaust. There also goes on the Engine light and i will check tomorrow what code it will threw out but i thought i ask here too. The Engine light only goes on when i do the full throttle and its stuttering. After the stuttering it accelerate just fine but i got the stutter in every gear but only one time. So if i floor it in second and got the stuttering, i dont have it in third gear when i floor it again.

I just put new sparkplugs and cables on it and thought it will be better but it wont. I think the problem could be the coilpacks or maybe bad fuel pump or filter?

[michi]

Just to say..., i had this problem for some weeks but it started to stutter really short when the engine was cold when i floored it. When the engine was warm it doesnt stutter at all and didnt happend after the first stutter again. Now it does it when the engine is warm too and often like i said.

[SuzukiGhostRider]

Sounds like it's running rich. Pull the code and let us know what it is.

[beretta]

my 96 Z 3100 sometimes at cold start will stutter a little but clears right up. if i feather the throttle real quick a couple times and let off it comes back but goes away. i dont notice anything while driving just when its sitting there idling randomly sometimes does this.

Doesnt throw codes either. but i had a scanner on it one day looking at some things and was watching miss fires and i feathered the throttle to get it to do the stuttering thing and it shows miss fire on cylinders 3,4,5,6 and the counts keep climbing the entire time its stuttering but soon as it clears up which is seconds the miss fire counts reset back to 0 on the scanner and nothing saves in the ecm, so whatever it is on mine its not throwing the engine light on.

I have never checked the plugs but the wires look pretty new, the guy i got it from was worried the oil was 1,000 KM past due to be changed and always took it to a shop to be worked on so im assuming the plugs and stuff are probably not that old since it seems to of been well maintained.

So maybe... coil packs or the module. something electronic anyways, i dont think its a fuel issue. but you having black smoke while driving is probably un burnt fuel so a miss fire some where.

[SuzukiGhostRider]

Like I said, it's running rich probably. That would be what black smoke means. And it only does it at full throttle so a miss is improbable or it would be constant.

[michi]

Okay guys, i drove around 30 miles today and the Engine light didnt came on... I had the laptop ready to read the codes but didnt got any codes. I noticed its some better than it was yesterday but still little stuttering when engine is warm. I will look at the weekend again if i get some codes and let you guys know.

[pghturbo88]

Spark issue is my guess. Could be weak spark from weak coils, and under load, the spark is not strong enough to ignite all of the fuel / air mixture, and thus the black smoke. You said that you never checked the plugs, they may be in need of replacement. NGK iridiums in my Mopar turbo made a noticeable improvement. A new coil pack (that SGR helped me to identify) also made a huge improvement in my minivan performance, even though it ohmed out correctly and "looked" OK.

[michi]

I put in new spark plugs and cables 3 days ago. But it doesnt get better at all. When the engine light goes on i get the code 15 (CTS Low). Could this cause my problem? I also noticed, when the engine light is on and i put it in neutral, the engine dies and when i start it back up it idles at 2500rpm. I also cant put it in neutral and rev the engine... it just dies.

[SuzukiGhostRider]

Yes, the CTS can cause issues like you're experiencing. That code tells you it's bad. Replace it