kingdaveofblair

iTrader: (1)

Well, this has been going on for a while, cant remember, before I put it away for winter stoarge anyways.

Sometimes it misfires, runs real rough. No power at all. Comes and goes. Lasts a couple of seconds at a time. If I throttle it hard, then the misfire goes away. Drive 2 miles, comes back, drive 30 seconds, comes back.....Very Random.

Then the next day, I will go for a cruise and it wont misfire at all...runs just fine and dandy.

Next day, misfire again....

Doesnt matter if its cold, or hot, warmed up, or


Ive got long tube headers with dual exhaust to the front of the rear axle with high flow cats and no mufflers. Ran great after the header/exhaust install for months.

Ported and polished MAF and TB. - unhooked MAF and took it for a drive, same symptoms.

I have the code P1157 & P1158? ? Insufficient switching... both banks

P0300 random misfire.

Ive searched and serched, but im not sure where to start now.

Should I go out and buy some new O2 sensors?

sroach20

iTrader: (31)

i had the same problem. mine turned out being that the wires that go down the passenger side of the engine contacted the headers and melted the crank sensor wire. it would have random problems untill i found it and rerouted the wires.

eamador11

^^ Yeah check your spark plug wires

kingdaveofblair

iTrader: (1)

nope, niether of those problems are it. Plug wires are great, and crank sensor wire is fine.... anything else i should check out?

kingdaveofblair

iTrader: (1)

Well, I bought a updated cartridge for my snap-on brick off ebay, so ill be able to hook it up to my car finally and go from there. Any more ideas would be much apprieciated.

sroach20

iTrader: (31)

have you done anything with the heads? sometimes the grounds that bolt to the back of the heads can be loose?

CanII

You should check your PCM for corrosion. I had a real bad problem with random misfires and it turned out to be a bit of corrosion on the PCM plugs.

kingdaveofblair

iTrader: (1)

Yeah, other than headers and a lid, its stock, so ill check the PCM connectors and see what that looks like. Thanks for the idea.

KW4life06

iTrader: (12)

Check your plugs. If theres any cracks they may still work randomly causing the misfires. Been there before... it might also help to get on a data logger of some sort to see if theres any specific cylinders that have any misfires recorded.

DevilDougWS6

iTrader: (8)

pull out your plugs, what do they look like?

LS1-450

iTrader: (33)

I looked through my tuning software & DTC documents & did not find P1157 or P1158. Although, there are P0157 & P0158 of which are oxygen sensor faults. If your code reader has noted codes P1157 & P1158, they may be manufacturer codes related to the PCM outputs that are sent to either the coils or the injectors. If this is the case, then it may be the PCM. What year is your car?