Multiple misfire - Help!

[SS_CTS-V]

Driving normal, but felt a jolt and the engine runs very rough, sounds like it’s on 4-5 cylinders. Raw gas smell is strong, oil pressure is good, but dash lit up like a Christmas tree, flashing CEL, service stanilitrak, etc.

Limped to a parking lot, no oil on the ground, oil on dip stick looks good. Battery voltage is good, all temps good… checked for spark on all 8, good. Fuel smell indicates fuel supply is good.

Pulled codes but all I can see is p0300 multiple misfire.

I have a tune, headers, and intake. Nothing internal.

Any ideas?

[SS_CTS-V]

Pretty sure I dropped a valve/broke a spring. Zero pressure in one cylinder. Got it towed home, will start disassembly tomorrow.

Head recommendations? Eye balling the TSP Brawler LS3 heads.

[1JEWLDSSRS]

Are you cammed? Or still stock cam..

[SS_CTS-V]

Stock cam, and this is actually the second time this has happened on the same head. First time was under warranty and they replaced just the one valve spring….

Just ordered a set of Trick Flow 255 assembled heads from Summit. Plus lifters, trays, push rods, and everything else needed. Wife unit voted for these over the TSP Brawler heads. Love her!

Cam will have to wait, but looking for something small daily driver, maybe the TSP Cletus Bald Eagle?

[1JEWLDSSRS]

Oh wow!! That'll do it everytime. Since you will have a good set of aftermarket heads, when you do go for a cam, don't go too small, after a while you will want a bigger one. I daily drove my Camaro with the TSP Stage 3 with a 3200 stall for 4 years until I retired. Was, and still is a great driving car, and a monster when she needs to be, even with the 4500 stall I'm running now!! It's all in how well it gets tuned. I just don't drive her every day anymore, have another vehicle for that now.

[SS_CTS-V]

For sure! I went conservative on my 2002 TransAm and regretted it. This time I’ll be sure to coordinate with my tuner and get what I want.

[1JEWLDSSRS]

Originally Posted by SS_CTS-V

For sure! I went conservative on my 2002 TransAm and regretted it. This time I’ll be sure to coordinate with my tuner and get what I want.

There ya go brother!! Get what you want the first time, so you won't have to do it again. Happened with my stall, my tuner said I would be happy with the 3200, well after about 2 years of that one, you almost don't feel it anymore, plus it had a "dull" between 3000-3400, so I fixed that and went with the 4500 with recommendations from Bo White, he was running a 5000 stall!! He was right, best change I ever did, changed the entire attitude of the car, for the better!!

[SS_CTS-V]

Current status:

Trick Flow heads installed with BTR rocker bearings and HD pushrods. Waiting on steam port block off to be delivered today. No one told me I'd need to block off the rear steam ports!

Hope to have it all back together and data logging for tune on Sunday.

[1JEWLDSSRS]

Originally Posted by SS_CTS-V

Current status:

Trick Flow heads installed with BTR rocker bearings and HD pushrods. Waiting on steam port block off to be delivered today. No one told me I'd need to block off the rear steam ports!

Hope to have it all back together and data logging for tune on Sunday.

Awesome! Getting closer. Good luck.

[wizard787]

Regarding the cam choice, I agree with the advice of not going too conservative. It's like choosing the right spice level for your favorite dish – it needs to be just right to keep you coming back for more without regretting your choices later on. Consulting with your tuner is key to finding that perfect balance, especially with the upgrades you've got lined up.