OK, here's the story. Thanks for reading, sorry its going to be so long.
I bought this '90 Pathfinder SE-V6 a few months ago, and put only 3 days insurance on it so I could change the timing belt (260,000KM just want to be safe). I was super careful to make sure I did it right, and took my time. Once I was done, I noticed that it was REALLY gutless. So, I changed all the cheap stuff: Sparkies, fuel filter, air filter, cap, rotor, wires. No improvement. Searching the forums, everyone says "exhaust manifold". I put this off as long as I could, then finally bit the bullet, borrowed a short drill, and called up some buds. 5 broken studs, and we fixed the manifolds. I expected an immediate improvement, but didn't get it. More research tells me that maybe my O2 sensor gave up in frustration. Where I work, we share a parking lot with a fairly reputable mechanic shop. They borrow stuff off us sometimes, and vice versa. Short story, I trust the guys. They said "don't just go replacing stuff. Bring it in, and we'll give you a deal on reading the codes and testing the exhaust." (they said they would only charge for the codes, but throw in the exhaust test). So, they scan the codes, and find nothing. He takes it for a spin, and confirms "severly gutless". He tests the exhaust, and confirms copious amounts of raw fuel, and will definitely fail emissions testing in December. OK, why? MAF sensor? Because he is a mechanic shop, he ordered up a MAF sensor and swapped it in. No difference. Cat? He pulled off the Cat, and said it looks fine. Timing? Knowing that I did it, and I am not a mechanic, (he gave me advice when I did it originally), he pulled off the top cover and confirmed that I have it bang on. Distributor off a tooth? He put a light on it and tweaked the timing. He also tested EGR, temp sensors, throttle position sensor, everything he could think of.
He sent me home on Friday and suggested I do a compression test. On the way home, I could not rev above 3K RPM, and have NO power. I have a fairly long commute through the city, and was a little worried about someone getting angry, but managed OK. So, fearing the worst, I did a compression test on Saturday. My lowest reading is 130PSI, and my highest is 160PSI (I have no idea how a "compression ratio" is calculated). OK, so my compression isn't perfectly even, but why the problems? Something the mechanic did is causing it to run worse then before, but what? I think that tomorrow I will see if I can get my cat off and check for blockages downstream or something.
If anyone can give me advice, I would REALLY appreciate it. Just now I finished confirming my timing belt, and tweaking the timing myself. I have it bang on 15 deg. One other thing. I am still a few thousand KM away from my next scheduled oil change, and already the oil is BLACK. I noticed that right from when I first got the truck that the oil goes black real early. The antifreeze was a nice brite Kool-aid green as well. Mmm that stuff looks tastey. And the neighbours dog that barks all night... just kidding.
Thanks everyone.
chris.
(long time lurker here, I love this site)
