When driving in automatic (sport shift), the transmission will go through all gears 1-4 before it reaches 35-40 mph. If I stay within this range, it will begin "lugging" down, like the rpm's are too low in this gear. If I pop it into manual shift I am usually in 4th gear at about 1000 rpm's. It does happen in 3rd gear also. When using manual shift, there are n't any problems with it at all. No check engine light has gone on, FYI.

There were no signs the transmission was going out-such as slippage

It has not shown any signs of going bad such as slippage until yesterday when it just stopped working

I'm changing the front valve cover gasket and want to adjust the valves if possible or if necessary.

I changed my oil head gasket it was sealed on really tight I had to scrape really hard to get it off and I finally put in a new one because old one had a leak then I changed the spark plugs also new battery and oil change when I took my car to get some gas it shut off like it had loss of power and now I can't drive it without it shutting off someone help me please !!

And if I let off the gas it stops or if I tap the gas while on the gas it stops

2-3 gear shift flare will it hurt to just keep using it instead of spending 1200 dollars to fixit?

Replaced o2 sensor recently.

Some days it happens only occasionally some days every time its driven.

Everything on the stereo is working but the volume, no noise will come out no matter what the volume is set at.

has a full tank of gas, strong battery.

I changed my catalyst both of them with new gaskets and o2 sensors replaced coil pack on 4th cylinder because it misfired corrected that issue changed valve gaskets were leaking new spark plugs put in move working spark plugs and injectors that worked to cylinder 3 still nothing checked compression it's good checked for spark it's good I'm out of ideas and this code didn't come up till I fixed cylinder 4 which is weird so now I'm lead to believe it's pcm board? The first misfire didn't happen tell gas tank got filled up 5 mins later started the first misfire on 4 but if gas station had bad gas wouldn't it affect all cylinders? The only one that is missing now is cylinder 3 any help would be appreciated thank you