ShevrolayZ28

iTrader: (4)

My car is running like poo after a H/C installation and I'm getting the old P0300 random multiple misfire. So I check the plugs, plug wires, swapped the 02 sensors etc but I found nothing wrong and there was no improvement.

Finally, I took off the DS coil pack so I could check to make sure the grounds on the back of the DS head were all secured. They were not! Aha! I forgot to tighten one of them down.

I didn't have time to finish up the job, I had to rush inside for a fantasy football live draft lol. So I'll put it back together tomorrow.

But so I can sleep tonight, tell me, do you guys think the loose ground might be my problem?

lunatik

What ever makes you sleep better,j/k. I have a 300 code im chasing but i think its a little different than yours. I was refered to gearchatter.com and somewhere in the troubleshooting it said to check the coil pack grounds. It was mentioned fairly early so it is a priority suspect. I've never touched my coil pack but...
Hope its the fix and get us some numbers after dailing that thang in.

mr2guru

iTrader: (16)

eh.... p0300..... had to just delete that code.... It's a typical camm'ed code. If I logged misfires per cyl. I would get a crapload at idle but hold the rpms at 3k and they would all zero out. Hense the random misfire. But you could also see if one cyl was getting abnormally more than any other. They were all even in their "misfires" It is just the lope.
I don't think p0300 has anything to do with why your car runs like "poo"

A ground on the other hand is possibility. EFI engines love good and many grounds.

ShevrolayZ28

iTrader: (4)

Thanks for the replies. I realize that the P0300 is a common "phantom" code on cammed cars. But with the way the car is running I think the code is legitimate. (My cam has almost no overlap so it should idle pretty smooth.)

I'm going to fix the ground, put it back together and see what happens. If I get this sucker running better I might be able to get it tuned today!

ShevrolayZ28

iTrader: (4)

The ground wire was the problem. No more multiple misfire codes.

lunatik

Cool, are you getting is dyno tuned or just tuned?

ShevrolayZ28

iTrader: (4)

Dyno tuned.

https://ls1tech.com/forums/showthrea...9&page=1&pp=20

lunatik

427/396! congrat man. I like to see the afr 205's perform. probably my head of choice or 225's depending on where i go with it. Nothing for now . Have fun with that power.