Hey there,

My engine was completely re-built from the bottom up less than 21k miles ago, just thought i'd throw that out there.

Two days ago I went to the store, when i came back out to go home, my car started running awful

The car is acting like it has a very bad miss, as in the car is shaking alot at idle, it acts like it wants to die sometimes at a stop light, it feels as if one of my cylinders are not working..

Today i pulled every one of my spark plugs, they were all tan to dark brown color, none of them were obviously damaged or anything so i have no reason to suspect they are the problem.

I then used an ignition tester on my plug wires, and all 8 of them checked out with extremely good spark.

My cap and rotor button are brass and I changed them out not 3 months ago, my MSD coil is less than a year old.

My fuel injectors are a couple years old now, i had them replaced a while back. I run fuel injector cleaner through my system as much as I can.

I have no idea why my car is acting like this especially ALL of a sudden..

Any ideas on why my car would act like it has a really bad miss?

 

Check to make sure that you don't have anything arcing. Open the hood up while the car is running at night and see if you see any fire works.
If all that checks out, check to see if you have any intake manifold leaks. Some times those bolts tend to loosen up a bit.
How does the car run when you rev it up and under load?

 

It still runs rough under load and when you rev it up you can tell there's something missing...

 

Just to share my experiance..Mine was doing the same and it turned out to be the pickup coil in the distributer.

 

How would i go about replacing that? And how much would that part cost?

I decided to go on a limb and replace all my spark plugs just to rule them out, i managed to get my driver's side cylinders (1,3,5,7) done in the little time i had yesterday, that didn't fix it, so if my plugs are the culprit, it's gotta be on the passenger side of the motor.

I hate simply throwing parts at it to try and fix a problem but i've done everything in my power to diagnose it... I've checked plugs, wires, for leaks, fuel pressure.... I'm at wits end here...

ALL i wanna do is make my car run normal again, i'll worry about go-fast goodies later..

 

First things first. Double check to make sure that the ignition timing is set properly with the electronic spark control wire disconnected. Once that is done, you can open up the distributor and check the distributor pick up coil. Check to make sure that you don't have any continuity between each of the terminals that plug into the ignition module and the distributor body. Next check the resistance between the two terminals. I don't remember what the exact specifications were, but I think it was between 250 and 1500 ohms. Double check the values in the repair manual.
While you are at it, you can remove the ignition module and take it to O'reily's or auto zone to have it checked.
Do you have the original distributor in the car? If so, check the distributor shaft play side to side. Should not move much. You can also disconnect the small white wire at the ignition coil, it goes to your tachometer. Sometimes when your tachometer goes bad, it can cause ignition problems. If it runs fine with that wire disconnected, you know what the problem is.
If all of that check out, it would not hurt to double check the resistance across your injectors. I know you said that they are fairly new, but sometimes they can get shorted out.
If all of this checks out, you may have to dig deeper. Sometimes a bent push rod, or a faulty lifter will cause the engine to miss. This is assuming that you have also checked you intake manifold for leaks and it is fine.
Also, don't overlook electrical connections, such as grounds. Make sure all are corrosion free and tight.

 

The distributor pickup coil is replaced by removing the distributor and unscrewing it from the bottom of the distributor body. The part itself is fairly cheep, I think around $20. But if you are going to go through the trouble of replacing the pickup coil and you still have the stock old distributor, I recommend getting a hew distributor. For about $120 you can get a nice, good quality distributor with everything, ready to drop in. To me it would be worth the money.

 

I guess i'll check for a bent pushrod and tighten down my lifters this weekend when i get home from school. As for now the only thing i can do is to stick in 4 more fresh spark plugs and hope for the best lol...

Cars are a freakin mystery at times....

 

Well, I switched out the other 4 spark plugs on the passenger side of the motor....

AND IT WORKED

None of the plugs looked like they were in rough shape, my only guess as to why a plug might have been bad would be that since the spark gap on AC Delco plugs are .035, and i gapped them out to .045, maybe one finally burned itself up?

I don't know, i just couldn't be happier that it's running the way it should be, i am currently giving the motor the SeaFoam treatment as i speak, i can't wait to smoke out my whole apartment complex here in about half an hour haha