Hi all I’m new here having a issue with my newish to me 3.0 100k miles it doesn’t happen all the time but it seems to happen more when I go up my steep driveway that I like to go up pretty quick but starting from a lower speed it seem when I get to the top and stopped temporarily it mis fires or something along those line never showed a check engine light I also feel it beats around a little at idle sometimes since buying the truck about 3 months ago I’ve replaced a good bit and cleaned

gates belt kit(belt, tensioner,idler pulley)
ngk coil,wires and spark plugs (tried to compression test but could not get the fitting to screw in)
delphi fuel pump
card one new cam synchro and oriellys sensor ordered the wrong sensor at first
fuel filter
wve pcv valve and grommet
cruise control deactivate switch and wiring
smoke tested
throttle body and maf cleaned with corresponding cleaner
cleaned every accessible electrical connecter

sometimes when I’m idling my Speedo needle jumps makes me think my alternator is funky looks to be an aftermarket reman unit
i afraid it kind of seem like the recessed valve symptoms as I’d like to get a jump on it before anything else may go bad
let me know what yall think and anything else I can test or replace I got mechanic experience mostly with bikes and quad so I’m not afraid and have a pretty good tool set
also who tunes these thing these days?

 

what is "recessed valve symptoms"? what valves? if the speedo is jumping I believe it could be a trans sensor. have the O2 been replaced? they wear out at 100k. a ELM Bluetooth scanner and Apps that you can get for your phone or tablet will give you lots of information to look at.

 

“Recessed valve symptoms” from what I’ve seen are intermittent rough idle, stalling, rough running in lower rpm,misfiring intermittently after going uphill
trans sensor may make sense for the speedo
I can hopefully replace the o2 sensors
the truck it’s not rusted have much corrosion

 

ok burnt valves, easy way to check it do a compression test. do a cold motor, remove all plugs. ck here or YouTube on how to do it. I had to replace heads on my 3.0 2 bad cylinders compression. had misfire , rough idle,

 

Replaced all 02 sensors today last night it did the misfiring a little longer than usual last night it was dimming my headlights almost sounded cammed again after going up my pretty Steep driveway

 

If your headlights are dimming, you need to look into that alternator.

 

Gives me an excuse to put one of those Mazda 130amp alternators on

 

Or Explorer. That's what I have in my truck.