My 2004 Outlander XLS AWD has a little over 150,000 miles on it. Recently I noticed that while driving down the highway I get these momentary feelings like I'm not getting gas. The feelings last just a fraction of a second and are very subtle. My passenger didn't notice anything, and I found that if I use the cruise control I don't feel it either. Looking online, the symptoms seem to point to the fuel pump. Agree? Is there a way to test it with basic tools?
Also, I started looking up fuel pumps at AutoZone and other places online. I see prices everywhere from $500+ to $17. It looks like the more expensive ones are for the whole unit, while the cheaper ones are for just the electric motor. Has anyone replaced just the motor? Is it difficult? Did it work? I've been laid off for a while and cost is definitely an issue. I see some that put out 100 psi, and others around 250 psi. Does it make a difference?
Thanks for any and all advice.

Follow-up: I was driving on the expressway this morning when suddenly the car lost power and the check engine light came on. Drove home in limp mode. Pulled the code and it was P2138. Googling I found that this was for the Accelerator Pedal Position Sensor. Also read that there was a TSB from 2006 calling for a PCM reflash to address this. Took the car (reluctantly) to the dealer. Charged me $125 to pull the code again and reflash. Seems to have solved the problem, at least for the moment. Only drove back home from the dealership on surface roads, so we'll see what happens when I get on an expressway this evening.

 

Well, it turns out I'm still getting the feeling like I'm momentarily not getting gas while cruising on the highway. My wife never drives on expressways and says she notices it while driving surface streets at 45mph. No codes, no limp mode, just a feeling like you took your foot off the gas for just a moment, despite having a steady foot on the gas pedal. I threw a can of Sea Foam in the gas tank to see if that would clean things up, but it didn't help. Any suggestions?

 

check fuel pump pressure before yoiu start throwing parts at it.