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need some help figuring this out. 98 xj 4.0 multiport injected automatic, starts and runns fine about 10 minutes then starts studdering, replaced fuel pump/regulator/filter assembly with no improvement. any help appreciated <img src="/forums/images/graemlins/confused.gif" alt="" />


We need a much better description of "studdering".. Is this at idle only? Is this at rpm only? do you hear popping and extra noise when it happens?

After about 10 minutes the system goes to a leaner mixture.. this leaner mixture burns a little better than the "choke" mixture and burnt valves show up better at this time.. Please give a more complete description..
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

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