That is not a completely true statement. The MAF can be disconected and the vehicle can still run in limp mode. The fuel regulator is to dangerous for the common person to work on (at least that is what the feds think). And 5.5mm is not that odd of a size for the DIS module. I have 6 sockets that size from those cheopo socket sets that you get at dollar discount auto stores.

 

I changed the plugs last week. The three on the driver's side a fairly easy because they can be seen with your belly against the grill. The front two (No.1 and No.2) are accessible from the wheel well if the body is jacked up. While you have the van in the elevated position you can access that last plug (No.3) from under the pass side door rear of wheel area. You will need that plug socket with the hex end and a (in my case) 3/4" combination wrench to get that bugger.

I have been having misfiring problems. The Ford dealer, after installing a fresh set of plugs, said I probably had a valve guide issue that was fouling some plugs. They suggested having them clean the engine with some kind of vacuum/forced air process that they have, or buy a replacement engine.

When I installed the new platinum plugs I first seated them in "non-foulers". These non-foulers increased the length of the plugs 'bout 1/2". That extra length increased the difficulty of installing the new plugs.

After the new plugs were in the engine stilled missed but differently.

I decided to buy and install new wires.

I replaced each wire one at a time, so not to install them in the wrong order. Wires were easier to install than the plugs.

The performance of the engine is better but, it still misfires, especially under load, i.e. uphill.

I Googled the firing order and found at about.com a diagram of a '91 Ford 4.0L. The distributor or what would be called a distributor in the stone age, is on the right or upper numbered cylinders side of the engine and turned 90¼. My wires are wrongly placed if this diagram is valid for the '93 4.0L. My placement of the wires are thus:
#1 to the first place left on the dist, #2 to the middle place left, #3 to the last place left. #4 to the first place right, #5 to the last place right and #6 to the middle place left. According to the about.com diagram I should swap #4 to the last place and #5 to the first place.

Which is correct?

BTW, should I replace any sensors, emissions shtuff?

 

On the coil pack the wires go like this.......

3 4
2 6
1 5
front of engine

 

Racerguy - I swapped the two wires at the coil pack so that they are as your post. The engine ran worst. Started ok, ran at idle. Kind of whistled and backfired on any kind of acceleration or under load. I changed them back. Still missing but better than with the last swap.

I still think it is electrical. Could it be valves?

dativer