Whats up everyone! So I have been issues with my car lately when it comes to the acceleration. Everytime I put it in first and drive off, it takes so long to build up speed. Everytime I am about to merge on the highway it takes so long for me to go 0-60. I noticed that I have to shift pretty early now because I feel it is adding unneccessary stress to my engine and I can always hear noise build up louder but not in the good way. The fastest my car will go is around 50-60mph. I tend to shift around 3k-4k rpms because if not my engine makes weird noises. I had to take it to the shop twice and I swear these mechanics couldnt even figure on whats going on. They ended up changing unneccessary parts that I doubt will maybe help my certain issue. The repairs I received so far are 6 new spark plugs, oil change, 2 new mass air flow sensors and oil filter. HERES THE THING, I scanned my computer for trouble codes and I got a (P0300 RANDOM CYLINDER MISFIRE) could this be the problem?? Thanks everyone!

 

Sounds like your car is in limp mode. You said valve covers were replaced, do you have oil in the spark tube seals / valve covers?