MAJOR CADILLAC TROUBLE!!! I got my valve cover gaskets replaced and now my car accelerates funny. It feels like I my car is shifting gears bad and my car always reads 0mph no matter how fast I go. I checked the engine codes and its saying e13, e24, e34, e52, e74, & e91. I was aware of the e91 & e13 but I'm not understanding why the other 4 showed up.

1. Worn clutch: If the clutch is worn, it may not be disengaging properly when you change gears, causing the engine to continue to rev as if you were still accelerating. This can also cause difficulty shifting gears or a slipping feeling when accelerating.
2. Dirty or faulty throttle body: The throttle body controls the amount of air entering the engine and adjusts the idle speed. If it's dirty or faulty, it may not be closing properly after you release the accelerator pedal, causing the engine to continue to rev.
3. Vacuum leak: A vacuum leak can cause the engine to rev excessively or idle roughly. The leak can be caused by a cracked or disconnected vacuum hose, or a malfunctioning intake manifold gasket.
4. Faulty idle air control valve: The idle air control valve regulates the engine's idle speed. If it's faulty, it may not be closing properly after you release the accelerator pedal, causing the engine to continue to rev.

First off , did you check fluid level ? any lights lit on the instrument cluster, check engine ? How many miles on It ? Ever change the fluid an filter ? can you manually shift through the gears.
DEFINITION: The transmission only provides first and second gear in Drive range. The shift pattern as the vehicle accelerates from a stop is 1-2-2-1. First gear ratio is 2.921:1 and second gear ratio is 1.568:1.
Control Valve Body Assembly
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A faulty 2-3 shift solenoid valve assembly (315B) is stuck On.

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Debris is found in the control valve body (301) or the control valve body spacer plate and gasket assembly (396

Check Tranny Fluid - Smell It - Does It Smell Burnt ?
If Not And Fluid Level good , Have The Tranny Flushed And New Filter Installed .
Other Things To Check .
Hamagilator Valve - It Works On Air Vacuum off The Engine and
Tells The Trans When To Shift .
Could Also Be A Bad Shift Silinoid
Thats Located On Trans Housing - Unplug Clean Re in Stall

yes. in order to change the rear valve cover gasket the easiest way to get it out is to drop the subframe which supports the motor from under the vehicle

I recently changed out all the plugs and coil packs on my 1997 expedition. After replacing them, the truck idles fine and revs fine but once it goes into gear it seems to way a million pounds. When I try to accelerate the rpms go up by the speed will only top out at about 20mph and the transmission will not seem to shift into the next gear easily, kinda jumps into gear. I found a hole in my pcv valve hose, I plan to replace it tommorrow. Could this cause my engine to bog down during acceleration and make it feel as if my transmission is going out?

a vacum line is ihe problem. check all vacum lines on engine and make sure they are where they are suppose to be

It sounds fuel related the fact that it idles rough and you lack power causes you to press the accelerator pedal more to to get the car to go which in turn causes the transmission to stay in 1st and 2nd gear longer bringing up the rpm's. The problem could be a bad fuel pump not allowing proper fuel pressure to reach the injectors This could also be caused by a bad fuel pressure regulator valve or a bad fuel filter all of these could cause low fuel pressure. It could also be a bad fuel injector or a throttle position sensor (TPS) could also be a bad (PCV) I would suggest having the fuel pressure tested first as I dont think your problem is related to the transmission repair you had done.

first of all you need to fix the motor mounts drive shaft hangers and the lower control arm bushings and if you still have a transmission problem . it is in the valve body in the transmission you need to bring it to a good transmission shopas this will be a major tranny overhaul

sounds from afar like a problem i had after installing after market spark plug cables on a diff. car. make sure you have factory-quality/ even mits. brand cables. (right parts vs. after mkt.?- no contest.)

inspect ur front wheel bearings... ..they sound like they are shot...worn...by what u describe..