Service engine soon light

Engine Mechanical problem
1999 Nissan Altima Automatic

Hi,

We have a Nissan Altima. The check engine light shows the code 1491. We had quotes for $400 from 2 shops. However, they are reporting different problem fixes. One shop mentions that the throttle position sensor needs to be changed and throttle body service. The other shop would replace the spark plugs and wires of the injection system. The car is now stopping at all red signals and shaking and stuttering at higher speeds as well. I have no idea about this. Could you please help me with this as I am so lost as to what needs to be done.

I'm pulling the following sequence in codes. 1 slow 2 fast the 3 slow 4 fast then repeats cycle. My wife advised the car would have sudden loss of power while driving. Idles fine starts fine just replaced distributor, any help would be greatly appreciated!

So last week after having minimal problems with my car for the past 4 years, it went crazy. When I applied the breaks - it shook, when I was stopped - it shook, it lost acceleration power up a hill and then, a couple days later, when I started my car and put it into reverse to get out of my driveway, my engine died. So, I took it to a really good and respected shop and they ran a test and got the error code: PO325. They then replaced the following parts: 4 Spark plugs, 1 Rotor, Distributor Cap, Wire Set, Fuel Filter and 2 Hose Clamps. Afterwards, my car drove fine for a few hours and THEN my Check Engine light came on. My check engine light has never come on before, not even before my car went nutty last week. So, my question is, could this be because they just replaced parts? Or could they have messed something up further? Or does my computer need reset? Help!

Alright, so should I get my car tested again to see if the code is still there? And if it is, replace the knock sensor? Also, what do you mean by "bad tune up"? I just need some clarification.

Thanks so much!