1994 Volvo 940 runs OK with MAF unplugged

[smelycat]

I've this 940 that appears to have a MAF that works most of the time. Of course, it may be something else. The car will run fine for a few days, then start idling awful, loses power, can't accelerate over 35mph. No CEL code light, We unplug MAF and it runs a lot better and CEL lights up. If I unplug the battery for 20 minutes and re-plug the MAF, it may run good for the rest of the trip, most likely it will act up again the next day. I've decided to list all the wrong things about this car and I hope I get a confirmation its the MAF or maybe some other idea's.

Exhaust manifold leaks at head. It was welded to head and the welds are breaking. I did not do it.
Cheap unheated O2 Sensor. I regret cheaping out on this.
Removed aluminum duct that feeds hot air from exhaust manifold.
New plugs
Have not checked distributor
Removed TPS throttle pos sensor and emptied oil in it. It ohmed OK as an open/closed switch
Sprayed MFS with MAF spray and Cleaned Inside Throttle body
I get a service light for 5 minutes when I start car, It goes away
Question, Would I have codes to read if no CEL?

Good Luck and Thanks. Mike

[lummert]

I would venture to suggest that the cast iron exhaust manifold cannot be welded to the aluminum cylinder head. Then I would suggest diagnosing the AMM (MAF).

[smelycat]

Your right ,it looks like they welded the manifold to the broken manifold studs.

Anyway, The codes point to AMM. I bought a Big C clamp that reaches over the headand its squezzing the manifold to the head better, I'm testing to see if the exhaust leak is faking out the O2 sensor
I jammed open the air box flapper to get cold air all the time to AMM. Stay tuned