Engine misfire cylinders?

And the exhaust smells as if it has a lot of unburned fuel. Maybe the downstream O2 sensor has died, so the ECU is cutting spark to cylinders 2 and 3?

No a o2 sensor would not cut out two cylinders bad or not check for spark on number 2 and 3 cylinders.Let me know if you have spark on those two and we will go from there.If you have spark then we need to check compression.Only three things really tie those two cylinders together spark same compression stroke and fuel injectors firing.My money is on spark first then compression issue. this guide can help us


https://www.2carpros.com/articles/engine-misfires-or-runs-rough


Please run down this guide and report back.

I checked spark with the 3rd from left plug against the header. No spark. Are the coils the next thing to check? Is there an easy way to swap them?

Voltage on the battery when running is over 14.2, also.

You can swap the coils from left right to right you jut have to take the four bolts out see if the no.spark follows the coil.Let me know what you find.

I swapped the coils, left to right, marking the original left, and the misfire still occurs on #2 and #3 cylinders, confirmed by disconnecting spark and injector wires. Still smells like gas. As you face it, the left coil feeds cylinders 1 and 4. The ignition control module didn't have anything visibly wrong with it.

Are you getting spark from the number 2 and 3 cylinders?If not then you have a bad ignition module.Let me know what you find.

Yesterday, I pulled the #3 spark wire and grounded it against the header: no visible spark, with the engine cranking.

If you have spark on the number 1 and 4 cylinders and not on the number 2 and 3 cylinders and its not the coil then the only other thing left is a bad ignition module.

Thank you!

Keep me posted on how it goes.

I bought a new ignition module, installed it and that did the trick, but not the idle is high and erratic. I removed and cleaned the spark plugs and removed and wiped off the O2 sensor on the header, figuring that the plugs and sensor might have gotten fouled with unburned fuel. No joy. Is there another valve/sensor that would have been fouled by the unburned fuel, or do you have other thoughts?

What codes do you have now?How high is the car idling?How many rpms?What kind of spark plug do you have in the engine?Not platnuim ones i hope?

No check engine light, yet. 2000, but up to 3000, sporadically. Stock Saturn dealer ones (?)

With that high of a idle i would check for vacuum leaks first.

Okay so I'm having an issue with the cylinders 1 and 4 not firing, they are on the same coil. I've switch coils and they still don't fire. I've also switched out the ignition control module, and still 1 and 4 are not firing. I am at a loss for what should be checked next. Thanks in advance.

Also it is not sparking from/at the coil so its not wires or spark plugs.

scan for a crank angle sensor fault check for power at the coils.

have misfire on #2 cylinder. replaced spark plugs, wires, fuel injector and ignition coil. ran better after changing out ignition coil. anything else we can try?

I would do a compression test on all cyls that's all u have left bedsides the ignition module computer and wiring to the ignition module that u hbent replaced.do a compression test and let me know what the readings are.

When he did the compression test on the cylinder it was about 60 - low. Thanks for the response.

was that the total pressure 60psi?if not what was it?let me know so i can help u figure it out.

sorry took awhile to get back to you. the engine finally just died and locked up. i think i'm just going to replace.

First of all thank u so much for ur donation it really helps keep this site going so we can answer everyones questions.sorry to hear ur engine locked up.did it run low on oil?if it locked up ur best bet is to replace the engine maybe u can find a used one.

my car skips at low speed. seems to be fine after a bit but is getting worse. Can't afford maitenence...help.

So are you saying the car misses at idle?If so does it smooth out at higher rpm's?Also you can't afford maintenance?You really can't afford not to do that.Because if you don't then it cost's a lot more down the road sooner then later.Also do you have any code's?

enter your question...engine misses, doesnt accelerate, dies when put in gear

How bad is the miss?Does the miss smooth out when you raise the rpm's up in park?Also what code's do you have?

not to bad.yes smoother@ higher rpms, no codes, engine has no power

Have you ever changed the fuel filter your due for a change at 100,000 mile's.I would also check your fuel pressure and have your exhaust checked for excessive back pressure.

It started losing power it would not go over fifty five mph and now it wont over thirty five mph. I checked the fuel pressure, key on it was 30 psi and dropped off instantly. I replaced the fuel pump, the pressure is back where it should be. I replaced the plugs and wires, the plugs were fouled and the wires at the coil were corroded. It drive okay cold, but as it warms up it starts surging and bogs out during acceleration. I only have a p0449 code that pops up. I attached a scanner and while running i get a cylinder misfire on Cylinders one and two.
What could be causing this?

Have you checked for a plugged catalytic converter that is what it really sounds like to me. That is the first thing I would check right now.

I think your are correct. After I posted it I drove it to warm it up so I could check the spark on cylinder two. While driving it during acceleration I heard a loud pop. It started running better. Power loss was gone I was left with an exhaust leak. I checked under the car and found the leak by the flex line. At that point I figured the catalytic converter was clogged.

Thank You

Which catalytic converter? the one in the exhaust manifold or the one underneath the car?

The catalytic converter under the car before the muffler.

Oh, okay you do not live in California or New York do you?

I have a 97 sl2 with error code p0302. I switched spark plug wires at the coil (#2 and #3) then get error code p0303. Would that mean the coil pack is bad?

Replace the spark plug wire. If the coil is bad you should still get a misfire on #2 the only thing you need was switch the wire and the misfire shifted to #3.

Wires and plugs were previously replaced and still have the problem. When I switched the wires at the coil, the misfire jumped to the other cylinder.

Test the sparkplug wires resistances if okay replace the coil-