04 stalls runs rough after warm up/4k rpm limit while driving
trying to help a friend get her liberty fixed, its a 05 with around 112k on it.
when driving under hard accerlation the motor cuts off at 4k rpm, like its hitting the rev limiter. it had been stalling on her at idle after it was warm, i cleaned the iac valve and that seemed to help (it doesnt stall anymore) but still has a rough(to me) idle. there are no lights on the dash. Any guesses on whats wrong??
well still didnt fix this. it was hard for me to work on cause she lives 45 min from me but she recently hit a deer and the jeep is now at my work garage so we can fix it so i figured id try to get the stalling issue fixed since it came back. i put new plugs in it but no help. also its a 04 not a 05. so if you start if when cold and just let it idle till it warms up it starts to stumble then will stall, start up again i dle for a minute then stumble and die. im going to buy a fuel pressure gauge this week and start there, just not sure why it would change after its warm
Check and verify fuel pressure. Make sure fuel pressure is sustainable under load. You put in NGK copper plugs gapped to 0.040" correct? O2 sensors can cause issues on these if the heaters do not warm them up fast enough. Badly fouled injectors can also play a factor. A good quality scan tool would make this a lot easier, as it will allow you to monitor fuel trims, important as it helps tell you what is going on inside the engine.
I put in whatever plugs the parts store dropped off dont remember what brand but i did gap them to .040. the weird thing is the cel light never comes on, there is a peerform service message though is this a cel light on these?? as soon as i get the some headlights in it im going to take it to get scanned, we have a good scanner but the garage we got it from is borrowing it as theirs broke and their a actuall garage that really needs it, were a recovery/towing company that fixes things sometimes. thanks for the help .
Never throw parts in a vehicle without at least knowing what brand the stuff is. Different types, and brands of plugs can have adverse effects on performance. In an ideal world, the parts store flunkies would hand you the right plug every time, but too many go to autozone, and will automatically hand you bosch plugs every time unless you request something better.