I have a 1990 Ford Bronco that after I drive it to town (20 miles there and 20 miles back) it starts to sputter, pop and back firer as I go up the mountain I live on. The clime is about 350 feet from the road up to my house and about 1000 feet from town to my house. I also have a very hard time starting it in cold weather. I have replaced the MAP sensor but it still does it can you help me with this problem?
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1990 Ford Bronco Question: Backfirers
Answer #1Superbob June 01, 2011, 11:28Master
This is a good question but I don't gather much particular information from what you've written. I assume you replaced the MAP sensor for the problem you write about. You haven't given me any history of maintenance or repairs so I'll assume you haven't done any recently.
I'd recommend is replacing the fuel filter if you haven't in recent memory. Also check the intake air ducting for loose clamps or defects that would allow air to leak into the intake. Check the sparkplugs for wear or cracks, check the sparkplug wires for condition, if they are too old the resistance could be excessive or the insulation could be faulty, causing ignition failure under load climbing your hill. One other possibility is that the airflow sensor (MAF) is failing, that's not uncommon for this vehicle. Any of these items could cause the hard starting. Maybe a complete tune up is in order with a diagnostic check to look for electronics problems. Get a Ford expert to handle it, you need someone with experience and knowledge of the problems associated with your model and year vehicle.
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Replykmpec, June 01, 2011, 14:05Rookie
I have changed the engine recently and have changed the fuel filter, MAP sensor, PVC valve, it has had a complete tune-up new catalytic you name it. The new engine has less then a 100,000 miles on it. Was told it could be Faulty Idle Air Bypass Valve because the truck experiences difficulty starting the engine when cold, stalling at idle, or hesitations during acceleration, it may be the idle air bypass valve. This valve helps the vehicle idle steady when the accelerator pedal is not pressed. What do you think?