99 Corolla Cylinder 4 misfire, P0304, New wires, plugs, coil. STILL MISSES BAD! HELP

[chubbygoatboy]

99 Corolla -- To make a long story short as possible, the car had 5 stored codes. Two Cyl. 1 misfires, Two cylinder 4 misfires, and one random, multiple misfires. I then cleared the codes.

I replaced spark plugs, and wires. Drove it, and immediately it was still missing. Codes now read cyl 1 and cyl 4 misfires, one each.

So, now it looks like maybe coil pack, since both 1 & 4 are on the same pack. So, I bought new coil pack and replaced it. Still runs like crap, and now I get only cyl 4 misfire. So I swapped plugs and wires around just in case one of the new ones was bad, still cyl 4 misfire, P0304 code.

I checked compression, and got 210, 210, 190, 190, so I think that looks OK.

The #4 plug is damp, and clearly not burning. HELP, and Ideas are greatly appreciated!!

[chubbygoatboy]

Originally Posted by chubbygoatboy

99 Corolla -- To make a long story short as possible, the car had 5 stored codes. Two Cyl. 1 misfires, Two cylinder 4 misfires, and one random, multiple misfires. I then cleared the codes.

I replaced spark plugs, and wires. Drove it, and immediately it was still missing. Codes now read cyl 1 and cyl 4 misfires, one each.

So, now it looks like maybe coil pack, since both 1 & 4 are on the same pack. So, I bought new coil pack and replaced it. Still runs like crap, and now I get only cyl 4 misfire. So I swapped plugs and wires around just in case one of the new ones was bad, still cyl 4 misfire, P0304 code.

I checked compression, and got 210, 210, 190, 190, so I think that looks OK.

The #4 plug is damp, and clearly not burning. HELP, and Ideas are greatly appreciated!!

Now, I switched coils to rule out the new coil being bad. It still has the same misfire code. So it appears that the plugs, wires, and coils are OK. WHATS LEFT?? Could the fuel injector do this??? Any thoughts are appreciated!!

Well, I have answered my own questions. So I will post what I found in hopes that it might help someone else!! I swapped the #4 injector, with #3, and guess what, the misfire moved to #3 cyl. So a new injector is on order.

[Brian R.]

Good job of troubleshooting!

[chubbygoatboy]

Originally Posted by Brian R.

Good job of troubleshooting!

THANKS!! And it did work. It runs awesome!!

[sayyam2006]

hi i have the same problem with my 99 Toyota corolla. can u tell me what u did to fix it please. thank u

[jabel1218]

I notice this post is super old but i'm having the same issues. Random misfire in cylinders 1 and 4 new plugs, wires, coil and already checked the injectors and they are working. What next any help would be appreciated.. Thanks

[danielsatur]

You might consider an ''Out of car injector service''
A local diesel shop can micro bath, blow out, replace seals, and test the flow rate on each injector, we have taken known bad injectors for a good cleaning.

[veedubmechanic]

Originally Posted by jabel1218

I notice this post is super old but i'm having the same issues. Random misfire in cylinders 1 and 4 new plugs, wires, coil and already checked the injectors and they are working. What next any help would be appreciated.. Thanks

Check compression. Probably bad piston rings causing oil consumption and carbon buildup.