multiple missfires?

[onoiocoko]

i got a 95 3.8lt. i got an engine light a few months ago and it went away befor i did anything, then it came back. i got it tested and it said multiple missfires. no specifice ones just multiple. i changed the plugs cause my dad changed the wires about a year and a half ago. roughly 5,000 miles. the light came back on but isnt staying on. and its still multiple missfires. i've been getting bad gass milage too. around 170-190 and i drive pretty good. not rought really. i replaced the fuelfiter already too. what could be the problem? my dad changed one of the coils too, i dont know if he changed them all or if u can only change them all? any help would be apriciated. thanks -nick-

[BillyCobin]

I had random misfires, replaced the fuel filter, plugs/wires. The car also had a hard time starting, it turned out to be a bad fuel pressure regulator.

[97GreenRS]

where ae the fuel pressure regulators on our cars? im having a problem with mine i think either that or the fuel pump. im supposed to be getting 55 psi of fuel pressure and im only getting around 40. i changed the fuel filter, and the coil's, plugs, and wires are new. at idle i get this thumping in the car. and im getting a SES light. how hard is it to swap out a FPR?

[onoiocoko]

a bad fuel pump probable wouldnt give me bad gas milage besides it not running efficently i guess? maybe it would though. i would also like to know where the fuel regulator is, ill try that first i guess. thanks for the reply though.

[daWhoady]

Could be your coils gone bad also

[onoiocoko]

well the thing is it usually doesnt run bad...but it doesnt have the same performance it had for sure. sometimes when i start it it runs kind of bad but thats about it besides gas milage. it really doesnt seem like a missfire cause it runs so smooth. at about 35 and 55 mph it shakes a little but i dont think its the motor unless its at a certain RMP...