I know these codes pop up on the forum all the time and I've read through a lot of the posts but Im looking for some personal input on my specific situation.

Just bought this truck about a month ago, 02 3.7 ram 1500. I'm getting two evap codes and a cylinder 2 misfire. I replaced the plugs since they were burned out to about .65 (104,000 miles) and the code returned. I swapped out #1 coil with #2 and code returned yet again, still on cylinder 2.

There is no noticeable misfire when idling or driving the truck. The only problem I have is cold starts, I have to crank it a good 3-4 seconds to get it to go but it starts instantly when its warm.

I guess my question here is what would be my next logical step in diagnosing this. Swapping out an injector? I hate throwing new parts into the wind trying to guess. is it possible a vacuum leak in the evap system could throw a misfire code in only a single cylinder?

I also want to add that I swapped coils in between resetting codes. Is there a chance that it had a code stored before i swapped the coil? seems to throw all 3 at once every time.

I appreciate any and all thoughts on this! thanks

 

You should check injectors next. If the problem persists on that same Cylinder it is time for a compression test to be done. That will confirm there aren't bigger problems at play.

 

Turn on the key to the run position, count to 3 or 4 or 5-------, then try starting it when its cold. you may just have a check valve that is allowing the fuel system to bleed pressure back to the tank. Mine does this once in a while too, just live with it unless you want to drop the tank and replace the fuel pump/regulator/filter assembly.

 

This is possible... doesn't hurt to check the injectors and get a compression test to be safe too.

 

Thanks guys, appreciate the responses. I let it build pressure and it starts normally. Are you saying this could cause the misfire code as well?

 

If it doesn't start if you don't let the fuel pump prime, then you might have a fuel pump problem, or a clogged fuel filter, or even a clogged fuel line.

a bad fuel pump could definitely cause a misfire, no doubt about it.

 

I agree with all the above totally, I just like to check out the simplest, easiest answers first. Nothing more irritating than spending money and time doing a bunch of diagnostic to find out it was something easy and simple

 

So driving to work this morning I had no codes, starting my truck after work threw a cylinder 2 misfire code along with 2 evap codes. I drove about 10 miles and stopped by napa and pulled the codes again and the misfire code had already disappeared. Any ideas on this coming and go so quickly? My understanding was there was/is a different code for misfires happening on startup.

 

3.7 engine has a tendency to pit the exhaust valves. Do a leak down test and listen for hissing in the exhaust, throttle body or pop ur radiator cap and see if u get bubbles. If u get a lot of leak out of any of them install a new cylinder head and gasket. Sounds like that's the problem and ur evap codes is most likely cracked hoses in the evap system, leaking purge solenoid, bad leak detection pump or gas cap. Inspect ur the evap system.

 

Get a compression and leak down test to be safe, that will definitely narrow down if the issue is an internal motor issue or not.

Next thing I would do is get a gauge on the fuel rails and see what the fuel pressure is at before, and during start-up and then during a run condition.

These types of issues are hard to find mainly b/c they are so hard to recreate, so just keep at it.