I have a 2002 Grand Caravan with 250K miles on a 3.8L engine. The other day, driving home, it suddenly started making noise and running rough. We pulled over and had it towed home.

I checked for codes: P0300, P0301 and P0303.

I pulled the rear valve cover (what a joy) and saw one broken valve spring (valve closest to the passenger side) on cylinder 1. The top coil broke off. I did not find the pieces. I have searched with a magnet on a stick.

Why would cylinder 3 be showing a misfire as well?

I am going to remove the Rocker Arm Rail. Then use the Rope Method to remove & replace the broken spring ($7 for a box of 4). My compressor is having major issues and I don't have time to fix it, so the Rope Method looks like the best option. I hope to be able to locate all the broken spring pieces.

From reading other posts on this Forum, I am hopeful.

 

 

I believe that the left most valve on cylinder 1 is the exhaust valve. Can the broken spring on this valve cause a misfire on both cylinder 1 and cylinder 3?
I was able to replace the broken spring. All of the piece of the spring were tangled together, explaining why I did not see piece floating around.
Putting the Rocker Arm Rail back on was a challenge. I had to work by feel to make sure the Push Rods remained in their Rocker Arms as I tightened the Rocker Arm Rail screws.
Still have more to put back together. Glad I don't do this for a living.