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sprinkles08, ASE Certified Technician
Category: Car
Satisfied Customers: 22815
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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I have a 1990 Na Fairlane. When I accelerate normally it just

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I have a 1990 Na Fairlane. When I accelerate normally it just coughs and splutters and backfires and has no power. If I accelerate really slowly it gets up to speed and drives ok unless I plant my foot.

The car had sat for a long while and this only started happening after filling the tank and driving 400kms.

Does it sound like a fuel pump issue or would it be something else?

Hello and welcome to JustAnswer!


If this started directly after getting fuel then the first thing I would suspect is a fuel contamination issue. If the fuel was contaminated with water or anything else then will cause the engine to run poorly. If this started just after getting fuel then I would take a sample of the fuel and see what it looks like. Make sure it's not cloudy and doesn't separate after sitting, isn't brown, doesn't smell stale, doesn't leave an oily film on your hand after it evaporates, etc.


If the fuel doesn't seem to be contaminate then the next thing I would do is check fuel pressure under load. If the pump is failing and causing low fuel pressure then it may run ok at idle and lower engine loads but will hesitate and backfire under harder acceleration.

Customer: replied 4 years ago.
Hi thanks for that, it didn't start straight after filling, it ran great for 400kms then started.. Could still be the same thing?
It's possible but less likely to be contaminated fuel if it ran ok for that long after filling.
Customer: replied 4 years ago.
Ok so that being the case, how do I check fuel pressure under load? The car has OBD but no one seems to have software to read anything before 1996. Is it an OBD thing or is there another way?
Checking fuel pressure requires attaching a fuel pressure gauge to the fuel line coming into the engine, the gauge will show how much pressure is in the system. If you don't have a fuel pressure gauge available you can sometimes rent them from larger parts stores.
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