Getting codes 12 43 43 43 42 21 55

Replaced O2 sensor
new champion plugs
new bosch wires
new coil

Nothing has changed

it is bad when cold

gets better as engine warms up

very random

when first started it revs up, idles down then when it finally idles low it will start randomly misfiring like it is running lean

when I take off from a dead stop sometimes it will run like crap for 100 feet then backfire and take off like a bullet.

Any more suggestions

I just ordered a new ElmScan so I can do some of my own testing ( Any other suggestions here ?)

 

the backfire could be from something else burning in the motor like coolant or something, it could be a blown head gasket, or it could be a bad fuel pump. any white exhaust? oil in the overflow? coolant in the oil? Good luck

 

Very smart opinion. ( I liked it.)

I checked the fluids, all looks well. No white smoke. No smoke at all for that matter.

I'm waiting for the elmscanner so I can see what the O2 sensors are reporting.

Lean rich etc during moments of crappiness.


My goal is to get it working like new first before I start modifying.

 

Sounds like from your Code 43 misfires and 42 Fuel pump circuit that you have a fuel issue. Check your fuel pump may be time for a new one. If you have a failing fuel pump then you can easily get misfires.

 

I have solved the Mystery.

I had the wires changed the other day by a garage while they were doing other work.

Today I pulled the wires to check the coil.

terminal 1 on the coil was rusty and dark gray while the other 3 were shiny silver.

I used contact cleaner and some sand paper. Then I applied dielectric grease and put it back together.

Tada. Runs like a new kitten.

Thanks for the excellent advice everyone. I'm clearing the codes and I'll wait to see what codes come back.

 

I hope they didn't charge you for that. They didn't notice the coil pack? I wonder if they left it like that hoping you'd bring it back in [:'(]

 

Thanks for the idea. Ill try that on another car of mine.

 

Maybe.

I don't think these guys are that smart.

I think they just do what they are told but don't think much for themselves.

 

Got the same problem with my 96 Neon got the muiltply missfire code and something about not enought imput to pcm (code 12)

did the same as you ... Wire good new
plugs new
Injector cleaner and Put one new injector in a while ago
coil box looks good didn't see anything.

 

^^^What kind of plugs did you use?