Help...suggestions?

[shifty]

1041159

92 4.0l wrangler.



Chasing a sputtering problem and I have replaced the following or fixed the following:



Plugs, wires, cap, rotor, fuel filter, resealed the fuel pump on the tank, new 02 sensor, checked wiring on MAP, all vacuum lines see to be tight and functioning, tightened the manifold bolts (per possible vacuum leak), checked fuel injectors and cleaned ports, cleaned out the CCV (PCV), some oil blow by but nothing like I have seen from some pictures on some of these message boards.



Jeep was used to tow a landscape trailer prior to my time owning it, not sure how much towing was done. The jeep sputters at all rpms, but less when driving at highway speeds? even 2k at 60 sputters less than 2k at 30 in 3rd gear?

just as recently as friday morning, for the first time it actually stalled in my driveway with a puff but not backfire out the tailpipe, I did not spin around quick enough to see what color it was. Fired it up and it ran like a brand new motor for 15-20 min with no sputter at all?? then of course it came back again....



I have not tested the CPS yet, could the timing be off from towing? stretched timing chain? could this still be a possible vacuum leak, clogged cat? how can I check if the cat is clogged? it passed MA inspection with flying colors in Feb...

[addsig]

 

[berettajeep]

1041165

My first thought is timing chain is worn.



you could always remove the cat to check it,if possible.



spray around the intake with carb cleaner,with it running.maybe you still have a vaccum leak and tightening it did not help.could be a bad gasket[addsig]

 

[MudderChuck]

1041171

The first thing you might try is to check the computer codes. Sometimes they will tell you when one of the sensors is bad or weak. If one of the sensors is bad, it will tell the computer to go into trouble mode and the motor can sputter some. Another thing is a cracked exhaust monifold above the oxygen sensor. You didn´t say how many miles it has, but experience tells me most of the inline sixes after about 130,000 miles get a little loose in the main bearings. Usually followed by an oil leak out of the bell housing or around the harminic balancer. The lifters sometimes get a little loose and can cause uneven idle. How is your oil pressure? Pull off the oil filler cap and put your hand over it, it will splash a little oil but there really shouldn´t be any noticable pressure there. It says in the book that the little flap on the fresh air intake to your aircleaner is necessary to supply the right amount of cool and warm air and can cause uneven running. If none of this seems to help I can tell you how to do a quick valve test. I´ve never tried it on a Jeep, but I seemed to have some luck with my Chevy by disconnecting the battery overnight, so the computer restarts and taking it for a moderate speed cruise. Some of the corrections the computer makes, are periodic and not constant.[addsig]

 

[MudderChuck]

1041172

One thing I forgot to mention was checking the cooling system for bubbles or foam when the engine is hot (careful). A small compression leak into the cooling system, will cause a sputter by putting a little steam into a cylinder or two. The coolant will usually go down but very slowly.[addsig]