I just installed a relatively new engine that had been sitting up for about 4/5 yrs. I did all of the necessary prepping procedures before starting the car.

Prior to me replacing my old engine, I swapped all of the ignition coils from the new engine and placed them in the old engine. I did this because of a serious hesitation on start-up, which happened just about every other time the car was started. When I took the car for a test drive I noticed that the car ran extremely rough and had a puttering type of idle. Soon as I put my old ignition coils in the car ran normal.

SO when I put the new engine in the car, I made sure to swap out the ignition coils from the old engine. When I fired-up and drove the car w/ the new engine in it, it has the same rough (puttering) idle. I'm not sure if this is attributed to the engine needing time to break in or if I should put the ignition coils from the new engine back in.

I took the car to Autozone and their OBD tool said that it detected multiple cylinder misfire (code=P0300). What can I do to fix this problem?

 

i think you need to replace your ignition coils...
it'd be better to find out which ones are not functioning, and replace those...as coil packs are pretty expensive.

i got misfire in cylinder #1, so im going to replace that ignition coil only.

 

Is misfire bad for the engine. Let say you driving the car like that and you trying to pass someone in high RPM like that?

 

The CEL should come on if you have a misfire correct? or is it a ghost code?

 

Not always. The ecu sometimes needs repeated or prolonged misfire events to trigger the code. Usually, you can tell it's misfiring because the idle is rough, the engine is rough with lost power on acceleration. It just doesn't sound, feel, or drive the same.

With a multiple cylinder misfire, it maybe hard to isolate which is the bad one so your best bet may be to get a whole new set that is totally new. Also, if a coil pack is good, there is not reason why it wouldn't work in both engines. Also, make sure the spark plug is good and that you can hear each fuel injector tick loudly. Hopefully, you will get to the point where the ECU will tell you which cylinder remaining is bad. At least you have two sets of coil packs--there's got to be a complete good set among the two hopefully.

I think misfiring will cause you to run rich (unburnt fuel).

BTW, by new engine, are we talking "new" as in junkyard or factory fresh?

 

If the injectors are ticking loudly is that bad?

The engine was purchased from a salvage yard. I pulled the VIN for the engine on Carfax to verify the mileage. The engine was clean as a whistle. It came out of a totalled car rental.

 

No... normal. I just meant you should easily hear them tick (ie. they are working) with a stethescope.

BTW, I got a brand new set of 6 coil packs for $200 off ebay. They come up every now and then. Solved my random misfiring.

 

Thanks for the info. BTW, I swapped the ignition coils around and I am no longer getting the multiple cylinder misfire code (0701). It seems that I was able to narrow it down to a misfire in cylinder 3 (0606). A new code just popped up as well, (0201) for ignition signal primary circuit fault.

What does that mean?

 

have you changed your spark plugs yet?
if so you might want to do that.
what another org member told me to do, is to switch the the ignition coil and spark plug to different cylinders, and see if the problem has moved...then your problem has been isolated.
eg. switch ignition coil from cylinder 3 to 1 and spark plug from 3 to 4.

until the problem is fixed...i wouldn't drive the car too hard.

 

Well I switched the cylinder 3 ignition coil with one from my friend's car and the code went away. I drove the car and the CEL light started flashing and stayed on. When I pulled the code, I got 0505, which tells me that there were no codes identified. The car still drives a little rough. Think that it will improve?

 

Okay. I ordered a new coil pack for cylinder 3 and I'M STILL GETTING A MISFIRE CODE!!!

Can anybody help me ?!!

 

Try changing the spark plugs. I had the same code 0701 Multiple Cylinder Misfire and I have new fuel injectors and all. So I immediately blamed the Bosch Platinum spark plugs I had in there for 3500 miles. Replaced them with NGK plugs and no codes for 1000 miles. No more rough idle.