pulled my codes on my troublesome 93. ONLY code (other than 61, which DUH I know the AC isn't working LOL) was 34.
34 is MAP Sensor Low voltage HIGH vaccuum. The proble is, I have a Hot Cam, which would cause low vaccuum. However, I pulled the connector off the MAP and tested the black/gray wires: 5 volts.
Went to test the Black/green wires: ZERO volts. WTF?!?! Is something wrong with my wiring to the MAP sensor? How do I test the MAP sensor itself also? Am I doing something wrong?
The MAP being screwed up would account for why it goes into limp mode, and won't rev, and sounds like it bogging, starving for air/fuel.
HELP!! I think I'm close to solving it!

 

You have to probe the voltage between the green and black wires with the connector connected to the sensor. That is the signal voltage coming OUT of the sensor.

 

not to sound stupid, but how do I do that? do I just teh plastic off the wire somewhere to make connection with the wire itself? Or is there a place they are exposed?

 

ok, just went ahead and put a new MAP on there, and it drives about 100000% better! It still has a high idle, and is little hesitant off idle, I still think something is up with the IAC, but at least it drives. The vacuum port on the old MAP was black and nasty looking, prolly some crud up in it.
How do I reset the SES light though? After firing it up, the light came on and stayed on.
Want to reset everything, and try and run it again. I forgot how fast this thing was! Now who's ready to buy it?

 

If the SES light is still on, you still have a problem of some sort. You could try clearing the PCM by (key "off") pulling the "PCM BAT" fuse (panel in end of dash) for 30 seconds. You are aware your 93 can flash the trouble codes on the SES light???

Clearing the ECM will also reset the long term fuel corrections (BLM's), and they need to be reset because they could be al screwed up from the faulty MAP readings. That might help clean up the rough idle.

 

how much vacuum is a hotcam supposed to have and how much do you have?

 

yeah, I flashed the codes, which is how I found out about the 34.
The light came on, cuz I'm stupid, and left the paperclip in the car when driving it LOL
I disconnected the battery, and the codes are cleared. That was at 11:00 last night. With the HotCam, Hookers and Mufflex, I wasn't about to troubleshoot it any more at that point. My neighbors already hate me enough!
I can't wait to drive it again, and see if it's all cleared up now!

Don't know how much vacuum I have, don't have a guage or datalogger.

 

A stock cam pulls 20-21"Hg of vacuum. I'd guess the LT4 HOT cam would be within 2-3"Hg of that. No way is should cause a MAP code, and even if a cam is big enough to cause a MAP code, its going to be voltage high, vacuum low (DCT 33), not DTC 34.

 

exactly, which is what made me think the MAP was faulty, which is was. How do I clean the port where it draws it's vacuum in the intake. the old MAP was full of gunk, and want to make sure the same doesn't happen again!

 

Check the top of your throttle body for a puddle of oil. Could be a sign of excessive blowby, plugged, PCV valve, etc. That causes the crankcase vapor to flow out of the passenger valve cover, through the hose that goes into the side of the TB. It picks up oil and the oil ends up in the top of the TB and bleeds down in front of the blades, where it gets sucked into the intake manifold. That's about the only "gunk" that can find its way into a dry intake manifold.

To clean out the hole in the intake manifold for the MAP sensor, open the throttle blades, put a vacuum cleaner nozzle near the hole for the MAP sensor, and scrape the hole out with a pick, pulling any chunks into the vacuum.