Ram 1500 has no power...any answers?

Question

99 ram 1500 4x4

plenum just replaced in june

The trucks been acting funny lately...not speeding up anymore past 4000 rpms...

Thought it was a tranny

but then today, i was driving down the road, and engined just revved and check engine like flashed.

checked teh codes, multiple/random cylinder misfires. Checked twice and all 8 were misfiring at some point.

cant get it above 2500 RPMs or itll just stutter and check engine light will flash.

Any other ideas?

99,917 miles on it now

60,000 pulling horse trailers.

cat's been tested...whole exhaust system is in good shape.

New plugs/wires/cap.

new tranny filter/gasket

any ideas?

after replacing the tranny filter, got it out on the road again to test it...same results past 3000rpms, but its misfiring cylinders 4 and 7 the most...

Answer 1

you need to spray some carb cleaner around 4 and 7 intake ports and see if its pulling air in to it,that might explain the miss-fire as to the transmission problem i think you may be loosing a transmission in it,does the engine rev higher than 3 grand and the vehicle not move with it or wont the engine go past 3 grand this i would like to know it might help solve this,good luck.

Answer 2

The check engine lite flashes because  the misfires affect the O2 sensors and the cat. converters could be damaged. I would suggest you test or clean the fuel injectors. That is most likely the misfire cause.