Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
working on a 99 dakota 3.9 with a misfire, not a dead misfire but kinda slight and can be felt.
i checked engine vacuum at the brake booster reads 19 inches and very solid not bouncing.
swapped spark plug with cylinder #2
performed injector balance test with a pulse tool all 3 injectors dropped from 44 psi down to 23-24
compression matches the cylinder next to it
sprayed intake with brake clean no change
checked spark from wire jumps 35kv nice blue spark
only thing kinda looks questionable is the distributor cap looks worn on the contacts
truk has 235,000 on it
Perhaps check for an intake-to-crankcase leak? As in, in the valley where brake cleaner won't reach. Plug off the PCV system and check vacuum at the dipstick.
Under which condition(s) does the misfire take place? Any clues from the freeze frame data? Is it speed/load related or more pronounced at no load /idle?
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