jrand, I'm not just throwing parts at it. I was - at first. I've been to several dealerships. Some tell me to replace the transmission ($4000), some say to replace the PCM. They are so UNSURE of what is happening I can't get any of them to commit to either one solving the issue. So instead of throwing parts at it ($4000) and ($760), I'm going to chance the PCM rebuild for only $170. I've paid the dealer diagnostic twice already and had a couple more dealers diagnose it for "free."
My coils and plugs are basically brand new. Replaced them in the past summer - and I barely drive my car. MIGHT have 200-300 miles on them. Cats are practically new-ish. Maybe 5,000 miles on them too. I've recently had my transmission completely rebuilt.
Here's how I came to the determination that it's the PCM. Long story short, I was driving the car one day and came to a sudden stop. I felt something weird with the car but didn't know what. Then I started driving and it felt like a slight misfire around 50-60 mph. I didn't notice it at first, the gf did. Everyday it got worse... One day I'm driving the car and it shifts harshly into 3rd, weird. Next day it's driving fine. Couple of days later I get harsh engagements into third and out of third. Then P D R harsh engagements. I take it to the mechanic. He tells me transmission, I don't believe him. Go to dealer, pay the $120. They tell me transmission. I get the transmission rebuilt. Same exact symptoms. I tell the mechanic, he opens the transmission - confirms he replaced everything.. valve body, solenoid, servo bores and bands... replaces the torque converter. Same issue. I try a used transmission from the junk yard. Same issue. Mechanic refunds me all of my money, junk yard does too - after several harsh conversations. After all of this I'm only out the dealer diagnosis fee and $300 for fluids.
Now to the fun part. What are the chances that I replace the transmission twice to have the same EXACT issues. After days of researching on here and talking to some members, I try the PCM. I get a used PCM for $300 from the junk yard. Put it in, and weirdly enough I didn't have to do any programming, maybe got lucky. Now I have harsh engagements into P D R and a SLIGHT engagement issue into 5th. 3rd is completely fine. That led me to believe PCM. Also the weekend before I moved I talked to a SR55 transmission expert and he told me that he's seen this countless times with our car and that it is for a fact the PCM. He actually had an LS sitting there with the same exact problem as mine that was waiting on a PCM. He told me this after driving my car... my shift into 3rd was so bad you can actually hear a clank below the car... he said with the tranny shifting that poorly I would get an E where D5 would be. The tell that it's the PCM is that it's not. He said your PCM thinks this is normal shifting, instead of thinking it's not normal and throwing the 'E.' I never got an E, and trust me it was terrible. Now it's not so bad at all with the junk yard PCM. My dad didn't even notice it. I did because I'm paying attention to it, but it's no where near as bad as it was.
Chances are there that the mechanic didn't rebuild it properly, and that the used transmission was also shot... but for all three (my original trans included) to have the same exact symptoms seems very unlikely to me. If this doesn't resolve my issue I will have the transmission specialist rebuild it again. He offered me a 4 year 50k mile warranty and gave me a really good deal. $1800 out the door - including installation. Either way I'll get it fixed, it's just a matter of when and for how much.
