# Start up good, hit the gas it cuts out.



## KGoodhue (Aug 29, 2013)

I have a 85 Nissan 720 pick-up, I start the vehicle and it's fine but as soon as I hit the gas it starts cutting out. Or dies completely. This only happens randomly throughout the day. It idles high, and low back n forth. It hates going uphill, and I have had the fuel pump replaced, the carb rebuilt and nothing is working. The jumper wire is connected directly, and I am about to give up. Please help!!


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## wilburk (Dec 29, 2012)

I'm suspicious of a faulty or cracked coil. Is it particularly wet or damp? Spark could be jumping out of coil and NOT to plugs.

I'd use a multimeter to check continuity of primary and secondary ignition coils. Haynes manual or FSM should give specs. 

Coils are a cheap replace and could save a lot of headache!


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## smj999smj (Jan 1, 2006)

The idle going from low to high (or "surging") could be a sign of a vacuum leak or lean mixture. When the rebuilt the carb, did they adjust the idle mixture? Intake gaskets are also prone to leaks on these engines; try spraying carb cleaner around the intake runners where the manifold bolt to the head (while running) and see if there is a change in RPM when you spray certain areas. This would be an indication of a leaking gasket. Even with the new fuel pump, it still wouldn't hurt the check the fuel pressure and fuel pump vacuum. Attaching a vacuum gauge to the inlet of the pump, if it's a mechanical pump, should show about 13" of steady vacuum.


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## BeyondBiscuits2 (Jan 18, 2006)

I had a similar situation when working on a friend's '70s Oldsmobile. It turned out to be a bad mechanical fuel pump. It was pumping enough petrol for the car to run properly at idle, but the minute to gave it throttle, it would die out. We only figured it out because we installed a clear fuel line, and watched the fuel only get halfway up to the carburettor. I know you said you replaced your fuel pump, but that doesn't mean you didn't get a faulty part or an improper pump. Just remember, the mass-produced aftermarket parts aren't always what they are cracked up to be. I second the suggestion about checking for intake leaks, Nissans and Datsuns have a notorious history of going bad.


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## KGoodhue (Aug 29, 2013)

K, so far I changed out the ignition coil out. It was filled with oil. I put on a new distributor cap because it was in bad shape. It actually seems a lot better. Made it up the hill without losing power. Although it still feels sluggish as if not enough power. I am going to try checking for vacuum leaks now because it is still idling a little high. So far everyone's advice has been useful, and showing results.


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