help this is confusing ok sorry about my english , but i need help
my neighbor always sees me working on my truck and she asked me if i could help with hers, i said sure, she said it was acting weird so she gave it to me , i took it for a ride and there was some vibration on idle but was fine on road , then went higway and above 20mph , it started to going crazy , it deaccelerate,and suddenly accelerate, deaccelerate,and on and on , take it to home and chek under hood.

grand cherokee laredo 96 4.0L 4x2
all under hod really dirty
dead battery
worn and squeaky belt on start
ccv and pcv hoses broken
ccv and pcv valves broken too
grommets really hard like stones
oil coming out from oil cap fill (oring really old)
air filter with oil from pcv hose
spark plugs wires broken and some extremly corroded (the one on coil was the worst)
distribuitor cap broken and burnt in the middle (the one from coil)
coil cracked
oil really dirty and old (like year and half old)
take spark plugs out and they were red and dirty , numer 1 and 6 black with burned oil on them, i think
radiator cap really old
coolant really dirty

so it was a mess , i start to work then
new battery change plugs for new champions to .35
new duralast wires
mopar distribuitor cap and rotor
ccv and pcv valves grommets and hoses
new air filter
cleaned throttle body
cleaned really dirty iac
flushed coolant and put new coolant
replaced radiator cap
replaced old coolant hoses
2 oil changes 1 for cleaning with some crc motor threatment on oil and then new fresh oil and oil filter new fuel filter too (the old one was extremly dirty).

so finally get all done , started and .............. wanted to stall ................. damn
checked all , all was fine , started again and rpm needle is like up and down veeery little, and rough start like wanting a lot to stall, so push the gas to 2000 rpm at the moment i pushed rpm go almost zero then all up and stable take foot from pedal and again rough idle, its warm now and stop engine, again turn key on and voila , all normal , no rough idle ,good temp good oil pressure, just fine , .......... what the hell?? ... turn key off again , and on again , all good , no rough idle no wanting to stall, repeat again , and all fine too, then take it to a ride on neighborhood and all fine no problems so far , just rough changes (probably old tramsmision fluid).
then went to highway , went to 20 mph and agaaaaaaaaaaaain start to deaccelerates and suddenly accelerates and then deaccelerates and up down up down , after all that work and money , stays the same.

took it home , and next morning , turn key on , and agaaaain , wants to stall , bad and rough idle , and when warm turn key off , and then on , and like the day before , all just fine .......... is driving me nuts.

found new shymptom , when turn key off , i can hear on the rear (i think the gas tank) a sound like clu clu clu like something dripping it last like 10 seconds, and always turn key off and i hear that sound for like 10 seconds when shut engine off, cheked fuel lines and they all fine, is that sound normal on cherokees?.

please help , what can this be, didnt change coil just seal it (can this be the one? , because there is spark and on low speed is all good with no problems), cant find whats wrong , no codes , no check engine , and always want to stalls on first ignition on morning , and when warm turn off and on , and is all fine , and above 20 mph goes crazy deaccelerate and suddenly accelerate , over and over under 20mph just fine, somebody please? some advice.

 

It sounds to me like a fuel pump problem. You'll have to put a guage on the fuel rail and see if you have the right pressure when it starts decelerating and accelerating. It's possible the pump has a leak inside the tank and what you are hearing is the pressure draining back into the tank. After all, you've replaced everything else, right?

It sounds like fuel starvation. It has enough pressure for low speed, but not enough for higher fuel demand at higher speeds. If the fuel filter was very dirty, there's a chance the pump intake screen is plugged also and the tank needs to be cleaned out.

I know of a case where really young kids put dirt in their dad's gas tank!

It seems amazing this thing was still running at all!

 

I second the idea that it is a fuel delivery issue.... pump or filter or injectors.


I also find it hard to believe this thing is running. You are a great guy to help her with this. She must be cute!!!

 

I realize it really needed everything you did to it, but did she freak at the price? She sounds like my wife's friend. Put gas in it and drive it until it dies, then call me!

 

I had to laugh... I had my ex-girlfriend come by work yesterday. She had dodged a chipmunk and put the side mirror of her 3 week old car into a mailbox. She was like, " can you fix it????" I got ready to make a smartass comment and instead called the dealership and ordered her a new mirror!
She had to buy the car because after we broke up she had no one to keep up with her car and... No oil equals engine death!

 

thanks for all the help , fuel is ok , the thing is , i have been testing and cleaning everything , and still the same , on parking push all trhottle and theres no hesitation, only on road it goes crazy, but now it does that crazy behavior on low speed too, but only when cold , when reaches at full temp , theres no issue at all , i even can run to 40mph and no issues....... this is crazy , there are no codes still , going to test tps later, can a blown head gasket cause this?

i took some pics but i cant find the usb cable of my cellphone

mmm im not sure last week was her birthday, shes 60 now ..........

she have a really really hot grandaughters but they only came to visit her every month, does that count?

 

I don't think it's a head gasket. If it was, it would be a problem after it warmed up. It might be dirty fuel injectors. Try running a good fuel system cleaner through it and see what happens.

On the lady, it depends how old YOU are. I'm 68 so it could be a possibility. The grand daughters would think I'm a dirty old man!

 

mmm im not sure last week was her birthday, shes 60 now ..........

she have a really really hot grandaughters but they only came to visit her every month, does that count? [/QUOTE]

Yeah, I would also try something like Seafoam in the Gas Tank and Intake. Again I have to commend you for helping this Grandmother with her Jeep.

 

Could there be sediment in the fuel rail? I didn't notice mileage. O rings for the injectors isn't that much money. A chance to clean the injectors. Hopefully injectors 1 and 6 are working and not leaking. Just a thought. If they are leaking those cylinders would not fire correctly and the fuel pressure would not be correct or steady. My fuel pump has 258,00 miles and still show 49 lbs of pressure at the rail.

How was the cam shaft sensor when you replaced the cap? Also Crank positioning sensor.

But I would definitely check the fuel pressure at the rail and see how quickly it drops off

 

again THANKS ALL FOR THE HELP , i really appreciate it




so i check the camshaft sensor , ........ maybe , jst maybe im on the right path , not sure since all my vehicles have coils and not distribuitor , im learning a lot right now

so the cam sensor is complety covered on oil and sludge ....... is not supposed to be like that , is oil all inside , and big leak outside distribuitor too , so i think seals are gone , probably thats the problem , but not sure , this thing is really expensive , so how can i know if this sensor its busted , can i clean it with carb cleaner or electric cleaner?, now im going for the crankshaft sensor ,and check it , (that one i think i found how to test it)

im going to look for a friend that can change those seals , i have never changed a distribuitor , and looking on youtube , it looks is not a easy task because the oil pump or something like that ,is not just pull out and in again, if i screw the timing , goodbye cherokee

so, back to work