Here's another option. The computer chip. When my car misfired, they replaced the computer chip in addition to the coils, wires, plugs. I suspect the chip was the real problem and everything else was $ in their pockets.

 

i cant tell you without knowing which cylinders

 

Ideally if you had a scan tool, it could tell you which cylinder was misfiring. There are things you can check without a scan tool though. Carefully inspect the coil towers. You are looking for cracks or signs of arcing. Misting the wires and coil pack with water from a pump bottle while the engine is running will help you find any arcing.

You can also check the resistance of each fuel injector. If any is out of spec it should be replaced. Unfortunately I do not have the spec for your car.

 

just ohm out each injector and whatever one is significantly higher replace it.


if you know which cylinder is misfiring, if its just one cylinder, try moving the plug wire to another cylinder or even the injector.

if its a pair of cylinders that share the same coil pack and they both misfire then its probably a coil pack issue.

if you remove the fuel rail and you see an injector leak onto the table or towel or whatever you have down, then an injector is leaking.

cant tell you exactly what it is without a scan tool, need to see fuel trim, 02 sensor readings for each bank, misfire data, and fuel pressure balance on all cylinders. and ohm tests for each plug wire. compression test wouldnt hurt either. back pressure readings would be nice as well

 

Here's another option. The computer chip. When my car misfired, they replaced the computer chip in addition to the coils, wires, plugs. I suspect the chip was the real problem and everything else was $ in their pockets.

I'd say the exact opposite. It's extremely rare for a PCM to fail. And when it does, typically the engine won't run at all. However it's VERY common for bad coils/plugs/wires to cause the engine to misfire.

Anyway, is the misfire worse at any particular time? Does it get worse in the rain, or in especially hot or cold weather? How about when you tromp on the gas? Also, don't assume the plugs/wires are good just because they aren't obviously damaged or worn.

I had a T-Bird with a set of Motorcraft wires that had been installed 5000 miles ago. It ran perfectly, *except* past 3000 rpm or so at wide-open throttle. Then it would fall flat on its face and feel like the car was running over rumble strips. I replaced all kinds of things, thinking it couldn't possibly be the fairly new plug wires. Eventually I replaced them out of desperation, and the problem never came back.

 

I would go with all 3 coil packs and the module. If the wires and plugs were good, I always suggested replacing them. Always noticed it to be a common problem.

 

i wouldnt throw coil packs at it without a reason

 

In my case it would misfire when I started the car in warm weather. Then after a couple of minutes it got better. So I ended up changing wires, plugs and coils with non-oem products. And it was fine for a while. Then the misfiring started again. Eventually it nearly left me stranded and threw a code. That's when the dealer again changed the wires, plugs, coils, and the chip.

I'd say the exact opposite. It's extremely rare for a PCM to fail. And when it does, typically the engine won't run at all. However it's VERY common for bad coils/plugs/wires to cause the engine to misfire.

Anyway, is the misfire worse at any particular time? Does it get worse in the rain, or in especially hot or cold weather? How about when you tromp on the gas? Also, don't assume the plugs/wires are good just because they aren't obviously damaged or worn.

I had a T-Bird with a set of Motorcraft wires that had been installed 5000 miles ago. It ran perfectly, *except* past 3000 rpm or so at wide-open throttle. Then it would fall flat on its face and feel like the car was running over rumble strips. I replaced all kinds of things, thinking it couldn't possibly be the fairly new plug wires. Eventually I replaced them out of desperation, and the problem never came back.

 

we rarely replace PCM's

normally on 3800 its either a coil pack issue or a injector

 

Its my wifes car and she took it to Auto Zone and they scanned and said multiple misfire or random misfire and that it was more than one cylinder. I don't know if they can detect which cylinders when there are more than one.

I am thinking about starting with the coils, and also replacing plugs and wires even though they are not that old.

 

take it to the dealer or get a hold of a tech 2.

unless you have x amount of dollars, to spend on a scan tool, take it to dealer, i wouldnt throw parts at it, have it diagnosed, it will be cheaper to spend 60 dollars to get it diagnosed properly, than to spend 100's on throwing parts at it.

regardless, do not drive on it like that, its not good for it

 

Try this. Pull one plug wire off the coil towers at a time. If any of the coil towers are brown and rusty corroded looking, that coil is bad and you need to replace it and the wires. Also, you do not have a replaceable chip in the pcm. It is serviced as a unit. Have you changed your fuel filter lately? This has been the cause of misfires that I have seen due to loss of fuel pressure. Don't just throw parts at your car. If you are going to fix it, you will need to either buy a fuel pressure guage and scanner that can help you diagnose it properly or take it to a reputable mechanic. There are those out there that are willing to help you at a reasonable cost. Let me ask you this, would you take out your appendix with a service manual? No you would go to the doctor. If it is too deep for you to repair, then go to a mechanic that is certified.