hello & need some help.

[99FLURP]

hello all, just found this great site, and just recently entered the MJ world. i bought a 1990 MJ 2wd 2.5L ax-4 bone stock, it was from the original owner, 58K miles. the truck had been sitting for many years according to him, until he recently tried to start it. so, i found it running with a lot of funny sounds from the motor. paid $1000. no rust, decent paint, thought it was a great deal?? drove it home under its own power. dad and i took off the valve cover, wow- a pushrod in two pieces and a sticky lifter. we replaced the pushrod and two lifters. changed oil, with filter, air filter, fuel filter, changed the plug wires, spark plugs, dist. cap and button, and put on new front brakes. it ran great and did not smoke. drove it for 2 1/2 weeks everyday lovin' it. now, this happens- filled it up with gas, parked it for maybe 2 hrs, then it started missing. if you attempted to drive it, it spit and sputters while the accelerating, as soon as you let off it regains itself and idles fine. when you start it up, it idles fine, but under any type of driving situation it spits and sputters and will die if you do not let off the gas pedal. so, today we looked into the tbi unit, no junk was found. we are thinking it might be the injector, or full pressure regulator, or tps sensor. but, dang these things are getting expensive. sorry for the long story, now would someone please school on fixing my truck, which would you recommend replacing first. my gut tells me it is in the injector, but $130 for injector, $200 for fuel pressure regulator, and $47 for tps (all prices from advance auto). thanks.

[jtdesigns]

The exact same thing happened to my truck to today... Since my truck is a 4.0 I'm thinking it might be a flipping fuel pump, or TPS.. Strange thing is, is that it started happening after I filled her up... Anyone have any good suggestions???

[aemsee]

Bad gas will make it have no power. Take a sample. You didn't put in e-85 by mistake, did you?

[99FLURP]

no i used 89 octane. tomm. i am going to change the injector. i will post results. fingers crossed:)

[jtdesigns]

No alcohol. Just 87. I might call the gas station tomorrow and see if anyone else was having problems.. It's never ran like that before.. I havent had time to check the TPS or fuel pressure, will do tomorrow. Is a loss of power/missing/skipping/chugging with good idle and running good after 3000 rpm's a sign of weak CPS??

[BLHTAZ]

The 2.5L (unlike the 4.0L) has a tensioner on the timing chain that will go bad. It is usually a sudden thing too and will cause the exact problem you are having. Try getting your engine at TDC and then look to see where the rotor is pointing or find the timing specs and check it out. The other items you mention are possibilites too, but it really sounds like a timing/ignition issue to me since it is sensitive to load/acceleration.

[99FLURP]

ok, this is what happened. today, i thought about changing the fuel injector at $130, then my dad said maybe it is the fuel pump. so, then we removed the fuel pump assembly and there it was. the piece of fuel line that goes from the fuel pump to the outgoing fuel hardline which is all part of the fuel assembly that sits down in the tank. well, the piece of rubber line had disinegrated. so we replaced a 5 inch piece of fuel line and yes, it runs like a champ. thanks for the replies.

[BLHTAZ]

Good job :thumbsup:

Now that you found that, I do remember someone else posting of finding the same issue on here a while back, but I had forgotten all about it. I'll have to try to remember it for the next time :cheers: