The 92 GT Mustang in my sig. Think of it as a "kissing cousin".

Lots of individuals with knowledge here I'd like to tap.

Last week, cruisng down the interstate, when... cough, cough, cough then down to 6 or less cylinders, CEL comes on & after about 60 seconds, it picks up runs normal rest of day.

Get home and scan the codes:

66, MAF signal low. or Sensor went below 0.4 volts or...

MAF sensor went below 0.4 volts during the last 80 warm-up cycles. or

TOT sensor output was less than Self-Test minimum value of 0.15 volts.

96, Fuel pump monitor circuit shows no power – Power / Fuel Pump Circuits or AIR Bypass (AIRB) not working – Air Injection or

(Service 87 code first if present) Fuel pump relay or battery power feed was open – Power / Fuel Pump Circuits

87.

KOER codes:

12, AIR system inoperative – Air Injection (pump is gone) 44 & 94 (Also Air injection)

I opened up the computer & there was cap leakage on all 3 so I sent it off to a chapter member who has done a couple cap replacements for us successfully.

I plugged it in today & it cranked and idled just fine for a couple of minuets till I saw a low coolant light & I shut it off to fill.

Then it wouldn't start. Pulled spout, & it cranked but ran like crap. Plugged it back in & it again started, but ran the same.

Check codes, 66. Pulled MAF connector & it runs just the same & gives a 66.

Any ideas where to start other than checking for power on red with key on? (I have 11.75 between red & black on connector at meter unplugged)

Any help appreciated.

 

One day bump to the top.

 

Two possibilities, the MAF really is bad or the PCM is damaged. Given that you found leaking caps I'd suggest finding another PCM.

P.S. If you had a tuner and could see live data you could confirm a bad MAF, the fact that the car runs the same with the MAF unplugged suggests the PC is ignoring it which point to a bad MAF, but leaking caps almost always means a damaged PCM. Have you got any other vehicles you could test the MAF on?

 

Don't think the one on my truck is the same pattern, but it crossed my mind this AM. Will look in a bit.

Was looking on stangnet & found a list of compatible replacements (meters) but chance of finding one just to test with are slim.

My repair guy said there was one or 2 traces that looked suspect, but measured out normal.

Still looking for some resistance values to check the meter against & maybe a Repair Analysis Procedure flow chart to follow.

The computer looks pristine compared to some I've opened or the original in my F 150.

 

FYI, you only need to replace the sensor portion of the MAF, this same part was used on a variety of meter bodies over the years and you just need to find a part with matching numbers.

 

Crap, it's looking like the ECU.

Pulled the trucks meter & whipped up a adapter harness for it.

Plugged it in & Mustang cranked fine, idled correctly for about 2 minuets...

Stalled & when I re-cranked it, it went right back to bouncing idle, 200 to 1200 and having to feather the pedal to keep it running.

Crap crap crap.

 

Brief update.

Shipped off ECU to these guys recommended off one of the Mustang forums:

https://www.ebay.com/itm/1986-2004-M...ht_10477wt_758

Just got a call from them & repair made & now paid, shipping today.

Diagnosis was corroded leg on IC near one of the replaced caps.

If all goes well, you might put them in your bookmarks for when the inevitable comes to your computer.

$161.49 or about what you'd pay for an average Cardone replacement.

 

Got back from Cruising The Coast a little early today & had some spare time.

Slipped the repaired & sealed with security tape ( life-time warranty) original unit back into place.

Cranked easily, idled & ran steadily.

Will check codes later this week, but I'm sure there won't be anything there that shouldn't be.