I am new out and here and a friend gave me the link. I am having issues with my Truck and need help badly.

I have a 96 3.9 4x4 Exten Cab that is driving me nuts.. Put a new long block in 48k ago and life has been great until now.

After about 15 to 18 miles, while still driving the truck will drop down to an idle and then jump back to running rpm. This causes a backfire through the throttle body. Or is will just cut off after the backfire.

The other thing I have noticed is white smoke coming from the exhaust... I know, I know thinking a cracked head but not loosing alot of water, maybe half a quart a week. Looks like the valve guilds are shot as well now. Some black smoke now when she starts. Going nuts with her acting this way and miss driving my truck.

The kicker is I have taken her to the shop and no codes, and the mechs there haven't a clue. Looking for any directions. I will post up a pick, once I figure out how. Good looking truck and been well taken care of.

 

head gaskets, water causing fuel to not burn then after there is so much fuel in the cylinders it will backfire, black smoke-valve seals
i would get the head gasket kit i just did mine(on my 5.2) a couple months ago and the kit wasnt very much

 

I agree with the above statement, except bad valve seals cause blue smoke (burning oil). The black smoke is most likely the unburned fuel hitting the catalytic converter. If you don't fix it soon, it'll need a cat also!

 

Yeah, take it from me, change the head gasket asap. Really, it isn't that bad of a repair, just plan on one day to take it apart and a second to put it all back together.

I find it hard to believe that a mechanic wouldn't be able to diagnose this, or at least take a guess at it. White smoke is usually a pretty good indicator.

Would you guys consider a valve job too?

 

Where I live there is a limited supply on good mechs. My fear was a cracked head but head gaskets are easy. Just the strangest thing with the rpm dropping and jump back up to normal running speed and the backfire.

That is what has me puzzled. I was thinking the worst in a Trans overhaul or a torgue converter going bad but no codes. I am about to pull my hair out but not getting rid of my truck .

Thanks for the tips and I will get a picture up tonight. I thought about a 2nd Gen but I like the body style of the 1st Gen. Like the 2nd Gen rims though.. going to have to look in to get those for mine.

 

The idling issue could be a bad MAP, TPS, IAC, or temp sensor, but none of those would cause a backfire. Still something to look into though.

And FWIW, 2nd gen rims have a wide offset on our trucks. I personally like the look they give my truck, but I know some people don't like too wide of an offset.

 

The rims give the truck a nice look and I like the wider tires.

I got the truck from my father when he purchased a Ford F250 . He babied the Dak and I could not see the truck going anywhere but too me. I was surprised at how well it drove and handled compared to the F150 I had.. notice the had .

Going out to get some pics to get up here.