My 4.0 is sputtering/running rough when I first start it?

[Nathan T]

Hi, I used to be a member on this forum under a similar name but for some reason it can't find my account (I had joined in about 2002-2003), but anyway...

For some reason my truck is sputtering when I first start it up. It does it worse when it's a warm/hot start. It used to only do it when it was a warm or hot start, but now it's doing it when it's totally cold too. I've always kept up with the maintenance on it. It has new plugs and wires in it. I replaced the MAF sensor last summer along with the TPS. It almost acts like a carbureted engine that's loaded up or something. I read another post on here saying that the alternator could possibly be the cause (leaking AC current into the wiring)? My alternator has some issues, the bearings are dry in it. I replaced it a couple years ago and got the 140 AMP? Explorer alternator for it from Advance Auto and it's always made bearing noise. So maybe it has more issues than I'm aware of? The fuel filter isn't that old either. It also has a new air filter in it.

Is there anything else that's known to cause this? It seems like when the MAF sensor went bad it sort of ran like this, but WAY WAY worse. My check engine light never comes on because of this. Any ideas?

Thanks.

 

[sothunter]

Check your vacum hoses . you may have a vacum leak

 

[Otto]

Are you sure you put the new plugs and wires in right? Sounds like something in ignition

 

[fireguy12117]

sounds like a possible electrical issue with either a bad signal to the computer from a bad wire or connection...or...engine temp sensor is possibly going bad, but not out of limits for the computer to detect. the engine coolant sensor is important for telling the computer what fuel trims to use at what time ie. cool start or warm starts.

 

[schroader]

Sound like a head gasket. If it does it worse when it gets warm and it sets and then you start it back up.

 

[parson2008]

yeah its a head gasket. mine does the same...

 

[parson2008]

i didn't think it was but it is. i don't loose much coolant but just enough when the truck is warm that if i shut it off for 10 or 15 mins that i start it back up the idle is all messed up and sputters. had shops tell me it couldn't be a headgasket. they thought it was coolant temp sensor, or iddler sensor, or plugs wires or coil pack, or leaky injector. well their wrong just today watched my temp climb and pulled over watched coolant bubble out. not bad headgasket leak but just ennoying.