Hi. I hope I'm in the right section for this. I've been fighting my car ('86 Iroc 305 tpi V8) forever it seems. It runs lean almost all the time. The codes 36 and 44 are reoccurring. It acts up (runs nervous) when it feels like it. Sometimes it runs like a champ and sometimes it stalls at idle. There's no rhyme or reason.


I've put a new computer,
IAC,
O2,
injectors (Southbay),
fuel filter & pump,
new intake gaskets,
fixed any and all vacuum leaks,
MAF sensor,
plugs,
wires,
cap/rotor,
ignition module,
EGR valve,
temp sensor,
EGR solenoid was tested for being good (it was/is),
checked ignition timing (it's 100% correct),
fixed some wiring back to factory (someone had played in the wiring and it was all messed up),
cooling temp sensor.




It's just a lot. Does anyone have any other ideas or suggestions? Thanks, Pinupdoll22.

 

DTC - 36 MAF sensor error

DTC - 44 Oxygen sensor error (lean condition indicated)

Have you checked fuel pressure with a gauge?

How are the maf relays? Still original?

Grounds for the relay control circuits?

 

I've checked fuel pressure with the Snap On fuel pressure gauge and it had 48 pounds.


I've changed the burn off relay and I believe the power relay (don't remember but I think so).


As for ground circuits, I back probed the whole wiring harness and it all seemed fine- per GM test procedure.

 

I *think* there are three relays over there? Maf power, maf burnoff, and fuel pump?? (its been a while.) I don't know if you can swap 'em around, but, might try that, if you can.

I suspect the maf problem is giving you the lean problem, given that fuel pressure is good.

 

I had a screwy Bosch O2 sensor(right out of the box). I was dataloging it and it was throwing my Air Fuel Ratio all over the place. Swapped it for a OEM ACDelco sensor and it evened out.

 

Add the TPS sensor to your list. They can get little dead spots in them and cause intermittent weirdness. Remember in 86 they were still using the kind you had to adjust into range following factory procedure.

If you suspect the MAF, unplug it as a diagnostic. It'll run without it, but in limp-home mode (with CEL on), but it should at least run consistently.

 

I recently replaced my O2 sensor with the OEM GM sensor...got it from RockAuto for less than $20.00 shipped.


I can't say for sure this is your issue, but that's pretty cheap.\


How's the play in the throttle shaft? GM didn't put a bushing in the shaft...not terribly uncommon to wear the aluminum the shaft is riding on to the point that you've created a leak between the shaft and throttle body housing, which would run the mixture lean, since the leak is past the MAF.

 

Checked for a vacuum leak? Old cars old hoses = vacuum leak.