my 79 240 is starting to hiccup. im not sure how best to explain it but its like your driving and some one taps the breaks? maybe like it doesnt get fuel for a fraction of a second or something? when i first got this car a couple months back i put some lucas fuel injector cleaner in and it did this very same thing but after a couple days it cleared up and i just assumed the lucas was working something out. but today it starting again. what could it be? what should i look for?

thanks!

i changed the spark plugs, oil, wireset, fuel filter, rotor/distributor cap, and oxygen sensor when i bought it.

If the hiccups happen with a full tank the problem isn't in the tank. The tank pump gets intermittent, but only starting - once it is running (as in driving down the road) it keeps running. Supply of electricity can get intermittent. Check the green relay for fuel below the dash by the hood pull. Replace it or look for burned wiring there. Make sure fuse 7 (and 5) are clean & cool, make good contact. Don't forget ignition. Terminals on coil and ballast resistor get nasty.
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-K (hope springs eternal)

If it's just hiccups then it sounds like the early stages of a fuel starvation issue. The in-tank auxiliary fuel pump may be dead/dying. Check the 700/900 FAQ and/or search the forum for articles on how to diagnose in-tank auxiliary fuel pump problems -everything from using your ear to using jumper wires at the fuse panel.
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Dave -940's, prev 740/240/140/120 Never overestimate what little I know.

Yeah, my brother's 260 had this issue. It took awhile to run everything down, but basically, it was a fuel supply issue. Start in the tank, and move forward, looking for leaks, bad lines, clogged filters, etc.

Best,

Lanval

I am actually having the same problem with my 79 242. Mine stumbles only under acceleration or with 5 people going up a hill, and if I back off the gas pedal, it returns to smooth running. The problem totally goes away if I pinch the return fuel line going back into the tank. I have replaced the in tank pump, hose in the tank, inline pump, cleaned the whole fusebox thoroughly and replaced all fuses with new, new fuel filter, k&n air filter cleaned up. I guess I am down to the pump relay that I ordered this week (it finally filled up with water and died). If this fails anyone have any other ideas? Car has been very well maintained with 125K miles on it, but the relay still has the 79 date of manufacture stamp on it. Sounds like the same thing, maybe the relay is all that is needed, if that somehow will cause weak voltage getting to the fuel pump.
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'67 122s auto 183K, '79 242DL auto 135K