ok i have a 1998 ford explorer sport with a 4.0l v6 and the thing used to fly like a bat out of hell with its high performance v6, 410 gears and for some reason it was running rich. now one random *** night it started running like **** after about only 10 minutes of use.. it wouldn't accelerate at all.. and a huge annoying sound comes with this loss of acceleraiton power. its almost as if air is coming up out of the front of the engine instead of out the back. now my mechanic, who is also my brother.. so no he is not taking my money, hes doing it all for free and has been a mechanic for 15 years. said we should replace my cats and muffler as that might be the problem cause they had to go awhile ago, so we did that but didnt solve the problem, altho it did bring back some speed in acceleration. he thinks a peice of the cat maybe clogged somewhere up the exhaust system. but we checked the fuel pump, fuel filter, and all the vacuum hoses.. everythings fine. but the car only reads 12psi when im flooring it, its losing vaccuum somewhere and we cant explain why which is why he thinks i beat one of the intake valves or exhaust valves. we checked the EGR valve its fine, and the computer has read no codes. we really cant figure out whats wrong with this thing which is why we think its an intake or exhaust valve. the engine still runs great though.. it wants to get up and go which is y im hopeing it aint no valve. but we tested all the spark plugs to see which cylinder wudn't change when we unplugged the spark plug so it would tell us which cylinder has a bent valve.. all of them changed the way the engine idled.. so that was inconclusive, but sometimes thats normal. so we really cannot figure out whats wrong with this thing, but after all this week it does seem like its slowly but surely improving everytime i drive it.. since i replaced the fuel filter it isnt as loud of a sound coming out the front.. and the air filter doesnt swoosh like it shud it actually hurts your ear if u put ur ear near it.. and it should never do that several mechanics told me including my bro. so hes saying exhaust is coming up through the air filter, but i dont see any fumes or anything. idk all i know is i loved this truck and i dont want it to be a problem not worth the money to fix.. im hopeing its something little and dumb. so please could anyone give me adivce. we also rebooted the entire computer in the car.. and for some reason its running default and it says the 02 sensors r off.. but this is because maybe it ran so shitty for so long with clogged cats.. idk. but 02 sensors and the computer wouldn't cause the loud sound coming up out of the engine when accelerating.. so it really baffels to me as what this could be. maybe the fuel injectors.. but i doubt it. idk, please help!!
Update:if you think its the 02 it might be but then how do you explain the loss of acceleration?
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Tell your mechanic to do a back pressure test to see if a piece of the cat did get lodged in your exhaust somewhere. If you have the old cats check inside to see if the honeycomb filament is still intact. You can also check it with a vacuum gauge. If your suspecting internal engine damage try a cylinder leak down test or compression test. As far as the mysterious noise coming from the front of the car????? Did you check the intake manifold for leakage? If it's a plastic intake the Ford's are notorious for melting where the EGR valve is. Good Luck and hope this helps.
Before u mentioned the 02 sensors, I was thinking exactly that. All I know is that on different cars the 02 sensor does make the car sound strange. Sometimes suffocating and a strangled sound and sometimes backfiring. If the cats and exhaust have been changed and the exhaust manifold gaskets are not leaking, I'm still thinking 02 sensor.
you have gotten gotten trash into the flywheel housing... water could have rigidity it in considering that those often rnt water tight basically dirt covers.... that or u did suck up water and ur motor is making noise..... use a mechanics stethoscope to discover precisely wer the noise is coming from and repost and consistent with possibility i will help u greater