gphilemon

1996 LS 400 misfires and smoke a little on acceleration, codes are 300,302, 308, compression test are good, right coil, plugs , wires , cap and rotor, EGR replaced, temp sending unit check out good, vacuum checks out great, all injectors work, fuel pressure is also good , but codes continue the same, any help out there?

LScowboyLS

I would clear the codes and see if the exact same codes come back or if the 30x numbers are different (such as getting a 301 or a 305 etc.)

some possibilities:

● jumped time by one tooth on only one cam
● defective cam position sensor
● defective crank position sensor
● MAF
● ignition system issue (igniter, coil, etc.)
● failing ECU capacitors


please do the tests in the service manual

gphilemon

codes are clear but same one came back, pull the ECU out and one capacitor has leakage

LScowboyLS

yay! - we have a winner!