1982 d150 lean burn.New coil, fuel filter, plugs look good, vac good, just smoged. Engine idles very smooth but when throttle is increased it starts to miss.Please note lean burn can't be removed by law in CA. There is a slight exhaust leak near the firewall. Any help in diagnosing this miss would be appreciated....Rich

Hmm, since msd boxes have a California Air Resources Board (CARB) exemption number, wouldn't they be legal replacments for leanburn on smog cars?

My '84 D100 idled well but had a miss. Turned out to be an intake manifold leak at the head flange surface. A new gasket with some Permatex Aviation sealer fixed it.

Cecil

Thanks Cecil, and to be more clear, I have no intention of spending the $ on msd on a vehicle I drive 1000mi per year and is worth $1000. any more advice would be appreciated....Rich

Have you pulled a spark plug yet to read how the engine is running? Brown/tan would be normal, White would be lean, and black rich. Sounds like a lean miss, which could be either a vacuum leak, or a fuel supply problem. You didn't seem to mention if the cap/rotor/plugs/wires have been replaced recently......might be a simple ignition miss. I wouldn't condemn the lean burn computer just yet. If it is getting spark, then the computer is probably fine. Also, you might want to do the factory tests as shown in the manual for testing the start and run pickups in the distributor. If the run pickup fails the start pickup takes its place, but usually doesn't let the engine run the way its supposed to.

Just some ideas to try..........

_________________
"That thing gotta HEMI in it??"

Just so we do not get too repetative...
http://www.slantsix.com/UBB/Forum16/HTML/008113.html

I still vote for weak spark, and I would start at the 9 year old plugs.

-S/6

Thanks for all the input. I need to get to work and report back. As Super6 points out there is more info on the other bbs, all very helpful. Thanks....Rich