Slow accleration, moderate jerking, noises

[chase3203]

My car recently died and after having it towed to a mechanic shop, I found out that they had to replace the fuel pump. After receiving the car back, I have noticed that my car is a little sluggish at times, especially when the A/C is on.

The car will run really sluggish on acceleration, almost as if there is a major drop in power to the engine. It always spurts/jerks moderately around 2.5k-3k RPM. It also makes the knock around 3k+ and when I give it lots of gas, the car jerks more.

I have also noticed when I shift it into 5th gear (final gear) on the highway, the car won't want to accelerate much over 70mph and the RPM usually hangs around 1.5-2k.

I'm not sure if this is a simple spark plug issue or a clutch problem.

 

[briannova]

I assume they cleaned the fuel tank and replaced the filter,,,, at least that's what I thought when I brought mine in for the exact same thing. I had acceleration issues, knocking, jerking, all the same issues as you mention just a few days after getting it back from the garage. I did a rail pressure test which registered 20-25 psi, and it should be above 30psi minimum. I decided to remove the tank myself, just to see if they even changed the fuel pump. The pump was replaced, but the fuel pump basket sock (filter) and tank were filthy and full of sludge particles. I checked the fuel filter, and they did not change that either. If you know for certain that the fuel filter was changed and the tank has been properly cleaned, my next guess would be the MAF sensor being dirty. Both are fuel delivery issues, and are most likely the problem.