My problem started after I did a small tune up of new plugs wires rotor and cap with a fresh oil change It still gets me too and from but My only thoughts were once you replace one worn problem another occurs She just seems to sputter in low RPM's and when she's warm. When she's cold and I run her there's no sputter so it throws me off. and runs good once I get at about 3500 rpm. I was thinking the same thing as far as my fuel pump needing to be replaced..

 

Ever clean your throttle body?
What spark plugs did you use?
I would think that a failing fuel pump would be more of an issue ABOVE 3500 RPM rather than below it.....

 

hmm havent cleaned the throttle body in a while and i used platinum 4 plugs..its weird though it ran great before I did the tune up and it wasnt my first tune up lol

 

Ditch the Platinums. I'll bet they give you your money back under a guatantee. Get some NGKs in that 4.0.

 

whats wrong with platinums? and it isnt a 4.0 its a 4 cyl i4

edit: i forgot to mention i checked my vacuum lines and a couple were disconnected so i reconnected them and it seemed to be running better for a few minutes but then got worse im losing patients and i dont know much about these motors anyone know a reliable xj mechanic near pomona, ca?

 

2.5 or 4.0. Neither likes Platinum plugs, especially Bosch.

Check the vacuum hoses below the throttle body. Use throttle body cleaner to spray around that area for vacuum leaks. It's not uncommon for the intake manifold bolts to come loose. No need for a mechanic.

 

ok thank you for the tips I will check and update any progress

 

finally got around to replacing the vac lines and that didnt help. Cleaned the throttle body that didnt help replaced fuel filter that didnt help. do you think that the plugs would really make a big difference? any other suggestions would be greatly appreciated

 

Those Platinum 4 plugs gave me fits once on my Alfa Romeo. And, a Honda. Return them for a refund and get Champion or NGKs.

 

Plugs are the first thing I would have checked and replaced, since they are the easiest to replace.
If they haven't been done in a while, might as well do them...

 

really?? what kind of fits?

I already replaced the plugs 2k mi ago with bosch platinums

and does anyone know about the intake manifold and if a loose bolt or manifold would cause this problem? Im tearing it all apart tomorrow but it would be nice to know if someone has a real fix for this problem or if everyone is guessing like I am

 

Platinum -4s caused an O2 sensor code all the way to California and back on the Honda. Even replaced the O2 sensor. Switched back to NGKs and no problem.

Alfa Romeo just wouldn't run clean and crisp. After much tuning of the mechanical fuel injection, I decided to put plain old NGKs back in. Ran perfectly.

Have you tried tighteneing the manifold bolts with the engine cold? Many times that works just fine.

 

thanks I will give it a try

 

Still think you should get your money back on the Platinums.

 

after a long battle with my jeep having the flu I finally found the cure! After finally breaking down and overheating for the first time since I owned the jeep I decided it was time to get dirty. My buddy came to rescue me and brought me 5 gallons of water since she decided to throw up all over the road. I got water in her tummy and I could hear it spewing right back out and since it was night time i couldnt figure out where it was leaking from. I hoped for the best and feared the worst but after babying it back to my buddys house I let her sit for the night. Morning time came so we headed out to see if we could locate her problem. Low and behold she was peeing out the side of her block but wee still couldnt see it. I decided to take off the manifold and there it was a pen size rust hole in the side of the freeze plug! Thank God thats all it was I feared I had blown the head gasket but after checking the oil there was no sign of milk or water. Went to Oreilly's and picked up new freeze plugs got them installed and walla! fixed! also found out I needed to replace the manifold gasket so took care of that as well and also re wrapped my electrical and cleaned things up. Then I took off the spark plugs and there was the reason for her cough! cracked plug! damn bosch! put new champions in let her sit for about an hr then cranked it over and wouldn't you know it she purred like a kitten again 200 bucks later shes back on the road and I am one happy camper!