ECU Tuning & Fuel Management - Engine Computer Failure??

Hello everyone who knows way more about cars then me. I bought my Civic Ex Coupe about 2 months ago. The check engine light came on about 3 weeks ago and after 3 different appointments with the mechanic, they have determined that it needs a new engine computer. Some friends are saying not to believe the guy. The engine light comes up with a code 5 and another time was a code 9, which i guess both have to do with the manifold sensor. After checking on those and finding nothing wrong, the mechanic said that it was the computer sending the wrong signals and that it should be replaced so as not to create other problems. The thing is, I don't notice anything wrong with the driving of my car...with the exception of a slight pause in the acceleration when doing hard acceleration. I have been told this is because it hasn't been serviced/tuned in about 70k. I guess my question is: does this really happen? Should i believe this guy? I mean I do trust him, but it's $485 total to replace it. If I do go ahead and do this, i was wondering if anyone knew of any places online where I might find a cheaper part. He is quoting $310 used. The part number is 37820-P28-A52.

Also, if i have to replace the computer, would there be an upgrade to at least enhance the performance? I mean, if I have to do it, why not spend a little more right?

Any advice would be appreciated.:eek:

codes 3/5 map sensor and code 9 is the #1 cylinder position sensor. both can cause a hesitation upon acceleration as well as driveability problems. as far as the ecu going out its quite possible, but now if he replaces the ecu and that isnt the problem will he give you your money back? local junkyards here sell the p28 ecu for $100. you could actually replace it yourself if you would like to give it a try. i personally cant say much, the technician should know what they are doing as far as the diagnosis. try finding a friend with a 92-95 civic ex/si and ask them to let you try out there ecu.

Well, I told the guy to order the part. I figured that i should believe him. I'm really skepticle about getting a part of that nature from a junk yard, especially the ones around here. I had to go away this last weekend, and over the course of the 3.5 hours each way trip, the acceleration began to get really shaky and, overall, it just drives really ****ty. Like the parts aren't running smoothly, it shakes and rumbles. I'm hoping that all this is due to the computer. I haven't talked to the mechanic yet, but i assume that if this isn't right, that he would give the money back? Is this not standard procedure though?