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Discussion Starter · #1 ·
I have a '87 Gn, pretty much stock. The owner before me said he had an after market fuel pump installed, don't know type or brand. When I turn my ignition on my fuel pressure guage shows 40, 20 when off. Over time since I have bought it, the car is cranking longer before it finally starts.(5 sec.) After the car has been runnig for a while if I turn it off and start it within 5 minutes or so, it starts right up. Also, every once and a while it starts right up from a cold start. Any suggestions?

I just recently replaced the coil pack and ignition module, since then I have slowly noticed the car running rough only when I am trying to stay at a constant speed. I notice it the worst between 45 and 60. If I accelerate through those speeds it runs fine. The spark plugs were new when the car was bought, since then they have been cleaned and re-gapped. I have also replaced the spark plug wires. Any suggestions?
 

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How long does the fuel pressure gauge hold pressure after you turn off the engine. Should hold for at least 15 or 20 mins.( rule of thumb)If you have stock injectors one or more may be dirty enough to leak fuel into the cylinder and cause a flooded condition. This could possibly explain the rough running condition you discribe and also why it does ok when you sock it to it.
 

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Discussion Starter · #3 ·
Thanks for the analysis. I checked my fuel pressure after I had been driving for a while. Seven minutes after I turned it off, it was already down to 21 psi and by 10 min. it was 19 psi.

I will try some fuel injector cleaner for a couple tanks of gas and see if that helps. If not I will have my shop look at the injector system. Do you have any other ways of cleaning the injectors, that also would help?
 

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When you turn your key on, does the fuel pump run for a couple of seconds?

Best way to clean injectors is to remove them and have them cleaned/flowed on an injector machine.

Better than buying a can of cleaner is to put a gallon of Xylene in the tank when you are down to 5-6 gallons of gas. Lot's more bang for the buck.
 

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Where can I buy Xylene?
 

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home depot, lowes, true value,Sherman Wiliams, most paint stores..some even have five gallon cans.

Answered my own question.
 
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