HappySalesman

iTrader: (3)

Hey all. I've got a stock 07 trailblazer with an lh6 in it.

I recently did a long trip (2300 miles) with a trailer on the back. Lots of up and down mountains, so there were extended periods of around 3-4000 rpms.

I've noticed the truck feels sluggish and has a noticeable random miss at idle, so I figured a tuneup was in order. I pulled the plugs on the drivers side, and this is what i found on cylinder 3 and 5


Cylinder 3

Cylinder 5

The electrode is basically gone on both of them. Cylinders 1 and 7 looked okay though the gap had opened up by about 5 thou.

These plugs only had about 25k on them before I took the trip (theyre ngk tr5gps). And this is the 2nd time I've done a long haul with this truck and had plug issues after.

Any ideas?

Full Power

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Yes: ADD FUEL.
If you look at your Power Enrichment, you'll see DELAY, which should be reduced to zero, Throttle position threshhold in stock tune is likely 90%, and I would reduce that to around 60% .
Make sure that PE is active down to the rpm where torque converter stalls. Stock tune may have PE setting minimum RPM at 5000 which is not helping you TOW.
I like to start around 9 percent PE at 2400 rpm, and ramp up to around 17% above 3600 RPM, but this will depend on how " STRAIGHT" you have tuned your VE table(s)
ie, if the factory has the VE jacked rich in the middle, than they really are NOT using PE for Power Enrich, they are just using it as abuse defense, so your teenager doesnt blow the motor running it at full throttle for 15 minutes in 2nd gear