allright guys, check this out. yesterday i start my truck, let it warm up and everything is great. then i put it rev and it just dies! kept happening too. put a new fuel filter on, cleaned the k&n and re-oiled it. didn't seem to help much, but i finally got it going and now at stop lights it acts like it's starved for fuel, lopes real bad, it misses when you mash the gas pedal too. it does run fine in park though. i'm thinking fuel pump, any suggestions? maybe someone else has had this problem? it's got new plugs and wires too. the truck is a 2003 supercab 2wd auto with a 4.2

 

Check the MAF sensor, the IAC, then go to the fuel pump. I believe you can do a pressure check at the rail to determine if it's fuel related. Hope this helps a bit.
I know when the MAF doesn't read air flow, it will just die, I've had this happen to me. I would definantley check these things first, because the pump is in the tank, and it ain't no fun to replace.

 

hi, i would also check for vacuum leaks particually if your engine has the rubber 90 degree elbow under the manifold.
the one fitted to my truck perished very badly but the engine still ran upto the point that the vacuum leak was so bad that the brakes stopped working.
good luck bokker.

 

hi,vlad 75 got your message the reference was to the inlet manifold and if i remember correctly the pipe goes to the rocker cover. again good luck bokker.

 

man this problem is a pain!!! i have checked pretty much everything, and can't find the problem, i'm not pulling any codes either!!! maybe a clogged cat???!!!! anybody got any idea's????

 

wow, i've been reading up on this motor for a few hours, and now i am scared, it seems like this motor is constantly plagued by problems. i used to love this truck, but i am really pissed that this issue is so hard to figure out! think i'll start looking for another old jeep with a straight six and a carbuerator, there are too many electronic components in these new cars and now long for the days when you could diagnose a problem without grabbing a scanner, a multimeter and a manual figure out that one of the seventy-two million electronic parts on a modern motor is out of whack. maybe i could just gut it and retrofit a 302 with a carb???

 

Welcome to the computer age.I know it sucks trying to find little probs with-in a managerey of electrical BS. As far as the reliability of the motor, it isn't so bad, just remember you are on a diagnosis site, you are going to see all the probs. Any, and I mean Any, motor is going to have it's share of issues. I'd like to know if the retrofit idea would work, haven't heard of to many sucess stories.
I'm with you on the Jeep idea, when I get that way, I just jump into my ol' 72 Monte and tear things up, then come back to reality when I hit the pump. Good Luck.

 

I have a buddy with a '97 with a 4.2. I have a '92 with a 4.9. The 4.2 is NOT a truck engine. I can't believe Ford retired the proven and venerable 300 I-6.

 

I would pull out the IAC (Idle air control valve) and clean it up and also clean the hole where it fits into. I have seen this happen on several cars and we just cleaned it up and they ran fine.

 

One other possibility is oil from the K&N fouling the MAF. This has happened to my 94 Mustang.

 

Unplug your MAF and see if it runs better.
If so, clean it and if that doesn't do it replace it.

.

 

I had a similar problem on my 97 4.2 with a manual trans. It ended up being a vacuum leak. It took a little bit to find it as the leak was rather small.

 

I had the same prob on my old truck but it fixed itself after the third try