Random misfire

[catrailrider]

Getting P030 code and blinking ETC under load from medium to heavy exceleration on my '04 6 cyl. Has new plugs and fuel filter. Air filter doesnt look too good so I'll replace today. Last week I put some Techron in the tank and was good for a week but misfire returned today. I noticed a little bit of oil around some of the spark plugs, not much. Thinking maybe the plugs are grounding out under load?

[djthumper]

P030 is not a complete code... how many miles are on the vehicle? What kind of plugs did you use? A little more useful information goes a long ways.

You may also want to do an introduction as well.

[catrailrider]

Sorry, I did an intro last year and havent posted much since then. I really like the knowledge and know-how of everyone on this forum and Im a proud member form the L.A. area. Code is a P0300 (random misfire) and it has 128,000 mi. and the plugs are either AC Delco or Bosch double platinum

[Cable810]

If you have the bosch plugs they might be the problem. Our trucks run best on Ac Delco Iridium. If you do have the Bosh I'd suggest replacing them and see what happens. Did this just happen or has it been going on for some time? Do you know when the plugs were replaced last?

[catrailrider]

I will double check today but they were replaced in September. Should I check fuel pressure? I may be overthinking this but maybe I got a batch of bad valves and they're not seating?

[TangoBravo]

I will double check today but they were replaced in September. Should I check fuel pressure? I may be overthinking this but maybe I got a batch of bad valves and they're not seating?

With over 100k I find it very hard to believe that your valves being a bad batch would be the issue, unless you have just had them replaced. Also I wouldn't say its a fuel issue but then I can't completely rule it out either. We need more details. How does the TB run? How long has this issue been going on? Exaxtly what spark plugs do you have(this is VERY important)? Have you cleaned the throttle body lately, if so how did you do it?

[catrailrider]

Looks like you were right. I pulled a plug and its a Bosch double platinum with the electrode burned off completely!!!!! Im off to Auto Zone for Iridiums....
http://i.imgur.com/viwk1jR.jpg
Thanks for your help. You rock

[tbangert]

Bosch platnum plugs are complete shit, I've never heard of anyone having any luck with them. I tried them in my last car and went right back to the auto part store 3 days later to buy NGK's.

Real friends dont let friends buy Bosch platnum plugs!!! Evar!!!

[TangoBravo]

Yeah our platforms really favor AC Delcos. Anything else even if its a good plug seems to cause problems. Just get what was stated above and you will be just fine.

[djthumper]

[06MidnightBlue]

Seriously...how many times has this been discussed?

Let alone the massive amounts of YouTube videos specifically made to explain how to diagnose and fix this issue for the TB?

[djthumper]

Seriously...how many times has this been discussed?

Let alone the massive amounts of YouTube videos specifically made to explain how to diagnose and fix this issue for the TB?

Discussed here and on GMTN numerous times which is why I asked those few questions. that I did in my first post...

[catrailrider]

My question is why are the platinum's even offered as a substitute? GM should should state "Iridium plugs only"

[plaen]

My question is why are the platinum's even offered as a substitute? GM should should state "Iridium plugs only"

IIRC the plugs originally in the early TBs were 41-965(Platinum) which were replaced by 41-981(Platinum), which both were replaced by 41-103(Iridium) and also used in 06 and later 4.2l

[TangoBravo]

My question is why are the platinum's even offered as a substitute? GM should should state "Iridium plugs only"

Because aftermarket support has rated thier plugs as comperable to AC Delco. So parts stores have decided to offer them because on the word of the aftermarket they "should" work, and they do for 90% of other platforms. Our platforms however is in that 10%.

[catrailrider]

Ok, so I threw the iridiums in last weekend and it ran great all week. Now I have a really rough idle and acts like it wants to die. Its better while driving and is not throwing a code. Any ideas?

[Diacom]

Just one, but if I tell you, it will cost you.

Hint, it probably would be easy to find yourself....

[catrailrider]

Well, I was thinking of cleaning the intake but I did it last year and doesnt look bad. Has new air filter as well

[dvanbramer88]

Dirty throttle body?

[catrailrider]

I was going to check that although I cleaned it last year. Didnt look bad when I changed the plugs