99 3.0 engine Misfire
 

ok so ive had this misfire for about a year and a 1/2 off and on. Ive replaced plugs,wires,coil pack,cleaned injecters,cleaned maf. ive also checked for vac leaks and have none. the code is poping for cylinder #5 i have good compression all along the board. But the funny thing is the truck will run amazing on warm days with no problems or codes. then once its sat over night and it get gets cold out the first start up that morning it happens again. Then goes away after i get to work and let engine cool start it up again and no problems the rest of the day. Im just stumped on what it could be maybe a bad pcm or ?????????? thanks for the input in advance!

I finally fixed the issue. After reading many threads on here thanks to those who gave there opinons on those threads. After replacing o2 sensors,plugs,wires and cleaning the maf. I sprayed around with some cleaner and found a vac leak haha a massive one at that. It was actually the intake manifold gasket on the passenger side. So I just went out and bought a gasket set which also included the upper plen gasket. Took about 2 hours to do and amazing no more misfire and runs smooth once again.

hmmm

i have had a misfire in cylinder 3 for a couple months now, changed the plugs and wires...still throwing codes. almost did the coilpack but it was off and on like you described so i didn't think that was it, i put in water remover for fear there was a little water in the tank and that has done nothing. I am getting sick of how much it stumbles when i give it gas and all the hesitation it has. How do i check if it is a vacuum leak? thanks

spray startin fluid around if theres a leak and u hit the spot with it the rpm will rise real fast then down.