A little history of the truck, bought new in 2005, its reg cab Fx4 with 5.4l 3v. Burnt the engine up before 100,000, Had to get another engine. before the 1st engine burnt up it was starting to give me some problem during hard exceleration, when you punch it to the floor to kick into passing gear it would start spitting and sputtering and back firing, I replaced the engine with a 2005 model engine that had 34,000 miles on it, with the replacement engine they used all of the same parts that was on my old engine to build the new engine, Well the same problem with the spitting and sputtering and back firing still exists under hard exceleration, sometimes it will go into cripple mode and shut down some of the cylinders if you try and push through the spitting and sputtering and back firing, sometimes it will drive throiugh it if you keep it hammered to the floor. When it enters cripple mode, you can shut the engine off while running and restart it in nuetral and everything works again till you try to excelerate fast again, I thought it had something to do with the Mass air flow sensor since I did put a K&N cold air intake on the truck, so I cleaned the MAF but it did not help at all. I am open to suggestions if anyone has any as to what the likely problem is. The problem did transfer from one engine to the other through the components that were reinstalled, but I dont know where to start to look for the problem. PLEASE HELP, I aint got no hair left to pull out trying to figure this out.

 

So I take it nobody has experienced this issue before.

 

these trucks DO NOT like the k&n filter elements. from what you described i would ditch the k&n and buy a dry element filter or oem, and clean the throttle body and maf sensor.dont forget the fuel filter,change that as well.

also get the codes pulled and post them, that will help tremendously

 

I would love to post the codes, but it has failed to issue a code at anytime, I was not aware of these trucks not liking the K&N cold air intakes.

 

something about the oiled filter, i forget what exactly but im sure a search on here would give a better reason/symptom for the k&n.
also perhaps you could get it scanned next time it goes into limp mode( borrow or buy a code reader) and before restarting plug in the reader

 

thanks for the input. that gives me a direction to look anyway.

 

Can I plug a obd2 scanner to the truck and leave it hooked up while I am going down the road and get any codes that may come up in realtime.

 

blueovalproud,
You can get live data if your have a reader that offers that function. I belive that any codes thrown should be saved in the ECU even with CEL off. From what I understand the problem with the K&N is the oil, it gets onto the MAF sensor which is right behind the filter and this causes bad sensor readings. I am thinking that you have a clogged Cat or injector issues. The injectors can get stuck open and then destroy the cat. That sputtering under power is what many on this forum have described prior to the bad cat diagnosis. Did you replace the injectors or are they the same? Do you hear any popcorn noise under floorboards when this is happening? Did you use the same Coils-Boots on the new engine?

 

Heres what I know for sure, The cats are not a problem, I had temporarily removed them and piped straight thru, that was a suspicion of mine at the start of this problem, I have since reinstalled the cats. I have cleaned the MAF sensor with maf sensor cleaner. The injectors are the original injectors they were just transfered to the new engine, I dont hear any popcorn noise under the floor board, The coil boots also got transfered from one engine to the other engine. Every part that was on my old burnt up engine got transfered to the other engine which was just a stripped down engine. From a dead stop or from any other speed if you punch it to hit passing gear, it starts bucking coughing spitting sputtering and backfiring, sometimes it goes into limp mode sometimes it spits sputters coughs gags and drives thru the problem, from a dead stop and punching it to the floor is starts to act up at around 2500 to 3000 rpms, yestersay I was out driving it and punched it and it started to act up and I just held it to the floor and it drove thru the bucking cough spitting and sputtering and started winding out the engine, but the issue presents itself around that rpm range. How can I check for injector trouble and coil troubles without replacing all of them.

 

what happened when you removed the cats? and how long have they been back in?
the cel should have lit up with no cats. and then there may have been problems with the pcm after reinstalling the cats. maybe the pcm needs to be flashed
also the cops and injectors are a good place to look since they have 100,000+ miles on them. it could be a good idea to do a full tune up. even though the motor may not have a ton of miles on it, you completed the long block with 100,000 mile parts.

 

Cats out I got a check engine light and it coded for the O2 sensors, it still ran the same with the cats out as it did with them installed. Is there a easy way to test the cops and the injectors, so that I dont have to replace all of them?