Multiple cylinder misfire codes

This afternoon the engine started making a weird noise and vibrations and the check engine light started blinking. I checked the codes and 3 appeared: cylinder 3 misfire , cylinder 5 misfire, and random multiple cylinder misfire. What could the problem be?

 

any help?

 

First try changing out your spark plugs if you haven't done that in a while. If still bad clean the MAF sensor. If more issues try 91 octane and run some fuel treatment.

Try this stuff first and see if your truck is running smoother after

 

crankshaft position sensor comes to my mind.. relatively cheap part, just sucks getting to it if i remember correctly. Multiple cylinder misfires lead me to believe that a sensor is dirty, or dying, i cant imagine three spark plugs would shit the bed at the same exact time, if at all...

 

Yup. Also check coil packs or look for loose connections.

 

Cleaned MAF, moved coils around and same codes appear

 

check crankshaft position sensor. I would bet that is what it is.

 

how do I check it?

 

took out coil 3 and 5, do they look bad? How can I know if they still work?

 

Mark them and swap them to a different cylinders and see if they follow.

 

Auto zone can check coilpacks to see if they work if I remember correctly but I doubt they are at fault.

 

That would see if a bad coil follows to different cylinders.

To test anything electrical you need a multimeter and check the resistance stated in a service manual. I don't have a 4.0l motor so I can't tell you the resistance you are looking for.

 

moved coil pack 3 and 5 to cylinder 2 and 4, erased codes and cylinder 5 misfire came up. That means coil packs are good, so what can it be?

 

How many miles on the spark plugs out of curiosity? It doesn't seem to be moving away from those 2 cylinders. Test the crank sensor resistance just to see if it is that guy. Maybe someone has the manual for your truck to give you a value to look for. Check spark plugs next look for lean or unburnt fuel. If the same cylinders keep missing you also have the chance of partially clogged injector

 

Took the truck to a shop, they said coils and spark plugs are good. They told me to check compression and fuel injectors, said that it can be a bad valve or bad injector.

 

Hopefully just an injector clog. You get injector codes when they aren't working

 

took the truck to a fuel injection shop, they checked the truck and said injector 5 wasn't receiving pulse and that the problem was the ECU, and that I need to change it??? WTF????

 

Anyone else has had these problem?

 

I'd believe a loose pin maybe. I'm having a hard time believing your ecu would go out compared to how much I've messed with my wires. Give urd a call see if I'm wrong. Figure you have an injector code rather than misfire. That sounds more like a p0205 code.

 

I still can't believe my ecu is bad, Im thinking maybe just change wires or something like that