I have a '97 Ram, 318. I was driving when the Check Engine light came on and the truck started a pretty severe shaking. It would decrease as I let off the accelerator, but as I gained speed, would begin shaking again. It ran ok if I was able to get up to a cruising speed (60-65 mph) and didn't have to decelerate or change speeds drastically. I checked the trouble codes and it came up 12...43...43...43.... I looked up the 43 code which came back as either 1) primary coil problem, 2) cylinder misfire, or 3) power to logic module interface problem. Does the fact that the trouble code blinked 43 three times mean the problem is #3? If so, what's the next step in fixing it?

 

A blinking CEL indicates a misfire, and my first guess is that you get that cat pressure tested at a muffler shop. If the cat is clogged, you're either running an original cat (which are known to be bad) or the O2 sensors have never been changed on the truck (indicating an emissions issue). O2 sensors should be changed ~60K miles regardless if they are throwing a code.

 

I'll check that out. Thanks.