Started a different thread yesterday but have entered another level of Hades today, so please forgive the new thread as I though the other thread was no longer relevant. Truck started fine yesterday & ran good for a bit over a mile, and it began to act like there was ice in the fuel line (acted like it was running out of gas & quit (no missing just stalled)). Thinking the near zero temp was a dead giveaway I added some gas line antifreeze, and back to normal. Left the vehicle sit for about 90 minutes, it started & ran okay for about a mile or so, and started missing badly & would not idle. The rpm's jumped widely if you tried to keep it running at 1500 rpm's to 5000 without moving the pedal and then it died. Tried to start it a couple of times and the new battery died, so left it over night. Replaced the battery this morning, checked the fuel pressure 38psi (thanks for the direction Savanna), replaced the plugs, and tried to start it. Still missing badly... So, if it's not the plugs, the fuel pump is apparently working just fine, there's no valve chatter (thought maybe a valve got burned or it jumped time), Magnacore plugs are new & seem to be in perfect shape, and the Ultragauge offers no codes, what am I missing?? Thought about a bad coil pack since the old plugs seemed to be black & smelled of raw fuel, but there doesn't seem to be much on here with the search I did. Help!!

 

Crank position sensor?? Sounds a lot like what my son's Jeep did when the crank sensor went out.

 

When the one went out in my Cherokee, it just died. Guess they could go out a bit at a time. Is there a way to test it or just buy one & hope.

 

Guess what mine did the same thing while out tonight in the cold 34* F, bucking, not idling like it was running out of gas, put it in park and watched the tps wandering between 15 and 7 idle also wandering , shut it off and then drove again about 30 min later drove fine but at idle the tps is now wandering 12.2/12.5 idle is elevated slightly

 

CPS's usually get finicky after the engine has warmed up. I'm unsure of the proper testing procedures; you're gonna have to google that one.

 

After reading your post again I have a couple more questions.

Do you hear any "ticking" while the engine is running? I'm thinking if you do it could be a damaged plug wire. Look for a blue spark at night/in the dark.

Disconnect the MAF sensor, does it run better?

How's your negative ground cable? Is it nice and tight at the battery terminal and engine block?

Check those things and get back to us.

 

No ticking at all. No blue spark; even sacrificed the hand by holding each plug with no shock. Just put in a new battery yesterday, so I know the cable is tight, and cleaned the connection to the frame a few months ago, so that should be good. Haven't unplugged the MAF, but will try that this morning (just unplug the collector at the MAF, right??). Did pull a couple of plugs last night, and they smelled like raw fuel. So I know there are cylinders which are firing.

 

What does the acronym "tps" mean? also always wonder what "CLE" means if you are so inclined...

 

Cel check engine light

Tps throttle position sensor

Maf mass air flow

Ckp. Crank position sensor

Iacv. Idle air control valve

Iat intake air temp

 

Tps - throttle position sensor

Cel - check engine light