Feels like a misfire but no CEL???

[Ratubbs]

So my '04 V8 feels like it has a misfire but I only feel it when going uphill at highway speed (70)... it sorta stumbles . I've changed the spark plugs (used denso's) 20,000 miles ago and 3 of the worst looking coil packs at the same time then when these symptoms showed up a couple months ago I changed out the remaining 5 coil packs ( all OEM Toyota BTW) ... as a side bar I did have two of these OEM coil packs prematurely fail both within the same week ... had a misfire on cylinder 7 first on a Sunday then misfire cylinder 1, five days later. Got them warrantied replaced and still the symptoms persist. Ideas.....?


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[Ratubbs]

...?


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[olhobbler]

fire or fuel...i didnt see if you did wires..i have 3.4 and it was a bad injector..but i will say it consistently misfired on the same cylinder according to diagnosis. i am not a pro but i was able to fix and it runs like it should since my repair.

 

[AuSeeker]

So my '04 V8 feels like it has a misfire but I only feel it when going uphill at highway speed (70)... it sorta stumbles . I've changed the spark plugs (used denso's) 20,000 miles ago and 3 of the worst looking coil packs at the same time then when these symptoms showed up a couple months ago I changed out the remaining 5 coil packs ( all OEM Toyota BTW) ... as a side bar I did have two of these OEM coil packs prematurely fail both within the same week ... had a misfire on cylinder 7 first on a Sunday then misfire cylinder 1, five days later. Got them warrantied replaced and still the symptoms persist. Ideas.....?

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Not sure this wouldn't make it misfire but have you cleaned the throttle body and cleaned or replaced the MAF sensor, also made sure the coil packs are getting a good connection?

fire or fuel...i didnt see if you did wires..i have 3.4 and it was a bad injector..but i will say it consistently misfired on the same cylinder according to diagnosis. i am not a pro but i was able to fix and it runs like it should since my repair.

There are no spark plug wires on 4th Gens T4Rs, they have a coil pack for each plug.

 

[Ratubbs]

Not sure this wouldn't make it misfire but have you cleaned the throttle body and cleaned or replaced the MAF sensor, also made sure the coil packs are getting a good connection?



There are no spark plug wires on 4th Gens T4Rs, they have a coil pack for each plug.

I did clean the MAF when I did the plugs.


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[DZNUTS]

Throw a boroscope down each of the intake runners. It sounds like the engine may be getting starved for air. Also, check fuel pressure. For some reason, your fuel pickup may not be sending enough fuel when in an incline at those speeds.


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