I have a 91 thunderbird 3.8. new everything new . dead miss on rev. Not on idle. Was running great then this happened. At a loss.
More details please… what all is new? How many miles? Has a compression test been done?
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I had a 92 T-Bird SC in high school. It developed a miss at one point. Turned out it just needed new plug wires.
+1 for compression test and what all is new…
When you say dead miss on rev but not idle, at what rpm does it start missing?? Will it rev over XXXX rpm or stop every time at a low to mid range rpm??
No experience w/OP’s car, but my similar vintage Corolla developed a similar symptom, noticeable miss or ping when accelerating, esp when accelerating going uphill . Problem was caused by too-wide spark plug gap. New spark plugs gapped correctly immediately fixed it.
This sort of problem, start with a basic tune-up procedure. Verify by testing that everything that is easy to check is properly adjusted, spark plug gaps, idle rpm, idle timing, new engine air filter, distributor cap & rotor, spark plug wires, etc. If that all checks out ok, move on to stuff not as easy to verify, fuel pressure, valve clearance, compression.
Presuming check engine light is not “on” of course.
New icm? Check
New coil? Check
New rotor? Check
New plug wires? Check.
Everything under the hood is brand new from oil pan to valve cover bolts. Onlything that’s not new is ignition module. And I had a spare one and put it on and did nothing. Car has gotten worse as soon as it gets any kind of gas it starts missing ts runniNg richer than bill gates. Idk. Motor only has less than 5k on rebuild. Maybe Ecu.
Yea no check engine light each cylinder is reading 150 compression. Brand new pump. Regulator, and filter. Could possibly be injectors they are the only thing I reused but had them cleaned
Anything over 1000 rpm it misses super bad. And ok tried texting spark and it’s got spark in all cylinders but every once in awhile it’ll show that #2 ain’t firing and then randomly fire again
Almost sounds like a cracked spark plug, pull #2 plug and look at it really well and or swap with a different plug and see if the random non firing changes cylinders with the plug…
If the plug is OK and the miss doesn’t follow the plug then swap (at both ends lol) 2 plug wires and retest for random misfire…
If misfire doesn’t follow wire swap, then check for carbon tracking under the dist cap…
New distributor/cam sensor?
Tester
Suggest to watch engine idling in total darkness. Do you see any weird lights flashing around the engine compartment? Ask helper to rev the engine a little as another test. If visible flashing noticed, a spark intended for a spark plug isn’t making the whole trip, leaking off to somewhere else instead. This is just the way high voltage electricity works, it doesn’t necessary follow the wires like low voltage does. The checking for carbon tracking idea above is a good one. When a spark goes astray, it often leaves a visible small track of carbon on the surface of wherever that happens.
My guess, either distributor shaft has some extra play, or the distributor rotor isn’t making a good connection to the distributor cap (underside) contacts. I’m presuming you have a new rotor and cap, but if the parts were sitting the shelf a while the contact surfaces could have oxidized a little. Ask shop to try cleaning the rotor’s and cap’s contact surfaces.
I took it to a shop around my house I’ve got over3500 in rebuild just fed up with it.
I would think a dist would give more of a random misfire over just a random #2 misfire…
But the OP said basically everything but the injectors, and I don’t think an injector would keep a plug from test firing (if not fouled out)… sounds to me like a plug got dropped before it was installed…
Although Georges post just made me think that the new #2 plug wire could have slipped a little out of the plug wire boot and could not be making contact at either the dist end or the plug end…
But that would be caught (hopefully) when swapping plugs and wires around to different cylinders…
If I had that problem I’d use my lab o-scope to view the hv spark signals on all cylinders. Easy way to discover ignition system abnormalities in distributer-equipped engines. Pre-electronic ignition, it used to be common for shops to use their Sun ignition system analyzer for this sort of thing. It basically did the same thing as my lab o-scope, only more elegantly. The night school auto shop class I took years ago had one, and I used it a few times when tracking down problems on my truck’s ignition system.