Bad Idle & Miss/Hesitation - 93 ATX

[93_SHO_FL]

Well, I have replaced just about every part I have read on here to replace and the car actually ran really well for about 4-6 weeks. Then out of no where the other night, it started idling very rough and missing/bucking off the line. Once cruising it seems ok however. When I slow down, idle is bad again, and then getting up to speed is a chore.

Here's what I have replaced thus far...

Cam sensor
Spark plugs
Coil pack
DIS
MAF
EGR sensor
EGR valve
vacuum lines (bypassed bad canister solenoid for now)
Battery
O2 sensors
D4U1 PCM
Fuel tank
Fuel pump/sending unit/pickup assembly
Fuel filter
Alternator (just did this Friday night)

There is a strange "howl/hum" sound from the MAF housing area that I have come to think may be related to this issue somehow. When the car runs bad and the AC comp stops working, this noise occurs.

The car seems to have a mind of its own I swear. I was running ok, kinda, with the AC off, but now it's poor either way. I thought it may be a volt/amp issue, since the alternator appeared be original (179k miles). So I put a new one on Friday night. No change.

Could one of my fans be going bad and over drawing the system, possibly causing misfire? Or maybe AC compressor dying and causing extra draw/strain on the system?

I don't know what to look for at this point. I got my scanner working and it came back with MAF under voltage and EGR issue. It also has code for the bypassed charcoal canister purge solenoid (but I have the vac lines all connected, bypassing it and it ran fine that way for a while).

The MAF I bought was a used unit, but was told it was good. But I know they go bad like crazy. Also, the IRCM (CCRM) is a 2005 replacement unit, but it seems to get so crazy hot being right over the radiator...could that be an issue also?

Any help is appreciated...as I am going nuts with this car. If I cannot fix it on the cheap, I will be forced to sell it and get something more reliable for a DD.

 

[rubydist]

maf under voltage is either a bad mafs or bad wiring to the mafs, and will need to be corrected to get the car to run right.

the charcoal canister purge solenoid bypassed is no problem, it does not affect anything except perhaps idle emissions.

I would reset codes, drive it a short time (10-20 minutes) and then pull codes and report to us what you find.

 

[LOUDSHO92]

Replaced the IAB?

 

[93_SHO_FL]

Ok, I haven't been able to do anything to the car since I posted this due to massive storms in central FL. However, it seems to be alot better all of a sudden. Occasional misfire when stopped. But no where near the horrible crap it was doing. This is exactly why I cannot seem to track down the root cause of the issue. It's so hit and miss. No pun intended.
Could I have a cooling fan motor going bad and maybe in the 90+ temps (which have not been in last few days) the fans are over drawing at idle causing strange electrical issues?

I'm going to order an A-Pillar gauge pod this week, stuff it with water temp, oil pressure, and volt gauges. Hopefully that will help me monitor it a little better since I do not trust the dash gauges anymore.

 

[93_SHO_FL]

Car has been running fine since my last post, occasional miss while stopped with ac on. Maybe the car had to relearn the new amp/volt level and adjust accordingly? I have no idea. This thing is gonna put me in the nut house!
Looking for gauges for my new A-Pillar pod now. Doing Volt, Oil Pres, and Water Temp.

All electrical senders right? Any tricks I need to know about hooking up the aftermarket gauges to stock senders?

 

[rubydist]

iirc, you need to use the aftermarket senders for the oil pressure and temp.

 

[93_SHO_FL]

Ok, so i better buy new gauges and not used with no wires right?