JacobChevys

Installed 1 7/8 Pacesetter LTS, with their ORY pipe. Upon first startup and drive I noticed the car run extremely rich and misfired and backfired. Engine when cold runs smooth for about 1 min then will backfire(gun shot like a .22) and is down on power considerably. Upon first inspection The back two plug wires got ripped. So, I put in all new set of TR55 plugs and MSD 8.5mm wires next to eliminate those, so no chance of a cracked plug or ripped plug wires and I have checked numerous times making sure all the plug wires are secured clicked onto plug and coil.
Got a code reader, Am getting p0300 and p0154(bank 2 sensor 1) along with the EGR and AIR codes after they were blocked off. So I changed the 02 sensor on bank 2 sensor 1. After 5-10 min of idling p0154 code never came back but was still misfiring.

After new plugs, wires, 02 sensor, Codes are p0300 and the EGR and AIR codes I forgot which ones.
Havn't driven for more than 10 minutes cause the misfiring and backfires would be so bad. I can also tell its coming from the passenger side of the engine. So finally pulled all the plugs. 1,3,5,7 are all firing clean. Plugs 2 and 4 are soaked in gasoline almost fouled. 6 and 8 still look brand new.

Ive checked all electrical connections, coil harness, 02 harness, everything is where it should be with no damage. Maybe Im missing something? Kinda stumped here.

If the 2 plugs in back (6 and 8) have no fuel and are not firing. Could the fuel injectors (6 and 8) be bad? Missing connection? Grounding out?
I can also post pictures of the plugs if that will help anyone. Plugs 6 and 8 literaly look brand new still.

Thanks in advance and Merry Xmas!

JacobChevys

I believe my problem is in the fuel injectors. I dont think a valve spring is broken or bent a valve. At least I am hoping... Am going to swap injectors 2,4---6,8tomorrow to see if the problem changes to the front 2 cylinders. Thing is the car ran flawless prior to this LT install this week. Owned car for 4 years never threw a code. Cant wait to figure this one out

JacobChevys

TTT

I pulled the valve cover everything checked out OK.

Still need to test/swap fuel injectors next to eliminate the bad two, I believe this issue has to be fuel related.

joecar

+1 swap injectors on bank 2.

64post

iTrader: (5)

The backfire is likely caused by exhaust leak somewhere, cold air enters leak and reignites unburned mixture, this is mostly happening when cold? Find someone with a smoke checker and you'll find it quick. Somewhere your new header install is not sealed up and it doesn't take very much leak to cause problems.

LilJayV10

iTrader: (39)

I'm pretty sure it's possible to somehow hook up the coils wrong on the 98's. IIRC there is something different about the connectors or something.

Does this sound right to anyone or have I lost my mind?

KCS

iTrader: (20)

Moving this to a more appropriate section.

joecar

I vaguely remember that the left/right coil brackets are wired slightly different on 1997/1998, I'll check a wiring diagram.

JacobChevys

Thank you very much. I should have the car started again by today

JacobChevys

Fixed the car!!!!
I had put the passenger coil harness on completely *** backwards.
Now im going to go enjoy the ride now, cant wait to get out there for New Years Day Drags now.

The passenger side coil harness was completely backwards, thanks for mentioning the harness it brought it to my attention. All good now!!!!

JacobChevys

Thanks for mentioning this, when you guys discussed the harness it made me go and check mine and realize where my problem was.

And no your not losing your mind, you were actually very correct!!!!!

LilJayV10

iTrader: (39)

Awesome man. Glad to hear you got it sorted out.