Originally Posted by chevyman70
Now, it shuffles out of lock-up on 4th gear between 40-50mph. Took it to the transmission guy, and he replaced the valve body and solenoids, but to no avail.
lockup related issues have multiple causes, but an easy one to check is that the brake switch is functioning and wired properly. depending on your cam, you may or may not be hitting the Misfire counter, and causing the ecm to disallow lockup. That part is a function of the tune, and you can't do much mechanically.
In addition to the transmission problems, I started getting p0171, and p0174. Long Trim is at 25%, even during idle. Short trim isolates between 0-6%. O2s isolate between .100 - 800. MAF is a bit erratic when I graph it on the actron reader. When I to read the hertz on the MAF, multimeter reads 0.00. reference voltage is 2.2 during idle.
This makes me think either the MAF is junk, mounted improperly, or has a damaged/loose wire. If you have a K&N type air cleaner, and oiled it, you may have also gunked up the maf. Unplug it, clean it with MAF spray and check its wiring harness. When you toss it back in, make sure its got a relatively straight shot to work on, and that its mounted in the upper 1/3 of the pipe. Its also possible there is a tune issue. At 0hz it would me MAF failure, which puts the engine into speed density using VE tables. A well tuned ve table should still idle and run OK without maf input.
I replaced the intake gasket, but the intake runners seem warped. I'll add it pictures. With new intake gaskets, the problem did not improve. Fuel pump read 52psi, jumps up to 60 when I disconnect the vacuum regulator. Replaced fuel filter.
Regulated pressure should be right at about 58psi, which is about what your getting when you unplug the vacuum line. That tells me the regulator is probably ok, but the vacuum source is not. Either your leaking out of the runners, of the plastic intake itself is cracked (or there is a tiny leak somewhere else that we aren't looking at). Have you tried carb-spraying for leaks while its running?
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