Don't know if you need to know are not but just Installed rebuilt motor, wife then burned it up so I had to have head worked on and put new gasket on. Now the problem has started

Have tried 3 different plugs, new plug wires ( and have switched them around also ) bought a new coil pack tried it then replaced with another new coil pack and bought a rebuilt fuel Injector, Reset light and it still keeps coming back on after 40 - 50 Miles
Haven't found a vacum leak either. HELP!

 

You need to get the P code for the Code 43, that will help narrow down the problem.

P0300 Multiple Cylinder Misfire
P0301 Misfire Cylinder No. 1
P0302 Misfire Cylinder No. 2
P0303 Misfire Cylinder No. 3
P0304 Misfire Cylinder No. 4
P0351 Ignition Coil No. 1 Primary Circuit
P0352 Ignition Coil No. 2 Primary Circuit

Could be any one of those. Check all pertinent wiring as well.

 

Comes up with P300, 01/01, which I take as misfire number 1 cyclinder. Have changed out plug in no.1, 3 times, have new wires and have changed them from 1 to 4 and have new coil pack ( Changed twice ) also reconditioned fuel Injector on no. 1 cyclinder. Have cleared check engine light each time I tried something, But the check engine light keeps coming back on ( after about 40-50 miles ) and still reads P300 - 01/01. I'm trying the 3 pronged plug for coil pack now ( it seemed to be a little loose so I tightened each connector )
Don't know if that's going to get it are not, I just keep trying different thing's
I've also dumped Sea Foam in gas trying to clean things out.

 

Have you pulled the fuel rail and cleaned it out? Sometimes trash gets caught in there and throws misfire codes. How is the car running?

 

Car running good, no didn't clean out fuel rail, I'll try that. I'm just having a hard time understanding why it takes 40 - 50 miles before it returns? (service engine light)

 

The PCM has to relearn the engine and sensors.

 

Cleaned fuel rail today, don't understand pcm relearn, I have cleared the codes everytime I've worked on, but it still comes back. AT least so far, haven't put enough miles since cleaning rail. Also had friend with me today and he says he can feel a miss every now and then.

 

light came back on today....disgusted! I thought ( I was hoping ) cleaning fuel rail would do it. nope. I still can't figure it out, it's been fine for two days and about 130 miles, now I get on highway and take it up to 70 and it comes back on. Doesn't make any sense to me....

 

When you changed the wire from 1 to 4, it still pulled up the misfire code on cylinder 1? Is there any oil on the plugs when you changed them out? The spark plug tube seals may be leaking in there and causing the code to pop up.

How is the car running? Do you feel the engine misfiring at all?

 

When wire was changed from 1 to 4, I cleared code and everything was fine until I got about 40 miles on it, then service engine light came back on. Everytime I do something I clear the code, yet it still comes back. I'm going to check compression today,when I do I'll be checking for oil on plugs.
Am I missing a vacum somewhere? Is there something I can spray around motor that might find a vacum leak? Seems I have tried everything and yet it still comes back on.
And why is it, it doesn't come right back on, that I can drive for awhile, and it would seem that I would have to get past 70 before it does? For the past few days I have babied and put on more miles, but as soon as I went on highway and got up to 70+ Light came back on? I really appreciate the all the feed back even though nothing has help as of yet.