Sure appreciate all the responses so far. I won't have time to really work on it again until tomorrow afternoon, but I'm wondering if anyone can help me make sense of the MAF situation.

When it was suggested I reinstall the old MAF, I had an idea just for kicks: pop the plug off the MAF sensor and see what happens. Very interesting result. When I take the MAF completely out of the equation by unhooking the wire, it almost cures the entire "miss" at low idle. Seems much smoother and the other thing I noticed is that on the Torque Pro OBDII gauge, the engine vacuum pressure goes up almost 5 points, from average of 25 with the MAF plugged in, to 29.9 with the MAF wire unhooked.

Please excuse my ignorance about this, but can anyone shed some light on what this means?

So then I quickly swapped the old MAF sensor in, and it does seem to run slightly better with the old MAF sensor. By that I mean the "miss" is somewhat less pronounced, but it is still there, and not nearly as smooth at idle as when the MAF electrical connector is just completely unhooked.

Thanks for any ideas on this!

 

My D2 ran lean over a year ago. I blew cigar smoke into the intake and noticed it leaking behind the alternator. Drove me crazy! I wanted to upgrade the wires & plugs. Spent money as I started the project as it consumed me.

I had to replace leaking valve cover gaskets and a disintegrated valley pan gasket. In addition I replaced the following parts: MAF sensor only, front upstream O2 sensors, wires, plugs, purge valve, brake booster connector to intake, barb connector to intake, t- body gasket, valve cover & valley pan gasket, coil packs. Once I started the year down I broke both intake connectors from brittle plastic. I also checked the elbow joints from the air box to the t- body. I also had to contend with the airbox neck that connects to the fender. I bought window tape at Lowes. It was disintegrated and broke in half. I also broke one fuel injector plastic cap in the process of pulling out the fuel rail. I bought a rebuild kit which consisted of O rings, caps, pintle filters. There is a YouTube video on how to do this kit.

Not telling you to do all of this but you probably have an intake leak. My lower intake bolts were not completely tight when I removed it as I noticed tearing it down. Probably where my leak was from the beginning. Do a smoke test. Don't be surprised if stuff breaks from being brittle. Stick to Walker, Bosch and OE parts. I installed Kingsbourne wires and Bosch coil packs & MAF sensor.

Here are photos:

 

Did you also clean the gas cap and spout?

What codes reappeared after swapping back to the old MAF?