2003 Expedition, check engine light flashing.
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2003 Expedition, check engine light flashing.
In advance thank you for any info that might help me figure this out. I bought a 2003 expedition with 191000 miles on it a few months ago. Truck had no issues till tonight. Check engine light is on and will start to flash every every few minutes. Truck starts right up like it was new but idles rough. Driving it still runs rough and when the check engine light starts flashing it really gets bad. Not a whole lot of power seems to be lost but it's still losing power. It's just a really noticeable miss. I've read some things about changing the plugs and coil packs, VCT solenoid, sea foam. I'm somewhat mechanically inclined but I'm no troubleshooter. Would appreciate if someone could lead me in the right direction. Thank you.
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First things first, get someone to hook a scantool up to it and read the codes. Do not drive it until you do, the blinking Check Engine Light is telling you that there is what is known as a "Class A misfire", which basically is a dead cylinder. This can cause damage to the engine and your expensive catalytic converters.
A cylinder needs 4 things in order to function: fuel, air, compression and spark. The fuel and air must in addition have the correct mixture ratio. In order to check for spark or fuel, if it idles rough you can unplug one injector at a time and listen for changes in the idle for each one you unplug. If you unplug one and idle remains unchanged, you may have found the issue. If that yields no results you can do the same thing with the coils, unplug one COP at a time and listen for a change in idle. If both tests yield no results, then it may be time for a compression test. This will all be simpler if you hook up a scantool to get the codes though, as it may have a misfire code on a specific cylinder.
A cylinder needs 4 things in order to function: fuel, air, compression and spark. The fuel and air must in addition have the correct mixture ratio. In order to check for spark or fuel, if it idles rough you can unplug one injector at a time and listen for changes in the idle for each one you unplug. If you unplug one and idle remains unchanged, you may have found the issue. If that yields no results you can do the same thing with the coils, unplug one COP at a time and listen for a change in idle. If both tests yield no results, then it may be time for a compression test. This will all be simpler if you hook up a scantool to get the codes though, as it may have a misfire code on a specific cylinder.
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I got the codes. I went and bought a cheap code reader at advance. It threw 2 codes the first time. P0171 an P0174. I erased codes and drove the truck for about 30 mins. No codes. Pulled up in the driveway and check engine light came back on. Ran em again and this time only 1 code. The P0171. What yah think?
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I had a similar problem, check the pcv hose on the passenger side that goes to the back of the intake manifold. I also found a broken vacuum line behind the battery. Replacing the Fuel Filter ended up fixing my P0171 code. I picked up a motorcraft one from rock auto for $18 plus shipping.
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For lean codes, PVC elbow is by far the most common, if the fuel filter is old that may also be a cause for it to lean out. Surprising that it did not show any misfire code. Does it have a rough idle?
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I ran my hand over and a visual inspection of the pcv lines and fittings. I didnt really see anything i thought was bad but one hose looks dry rotted. Should i pull them out to do a better inspection? I started the truck this morning and it seemed to be running ok. Its really cold here this morning. Im gonna definetly change that fuel filter today. Really appreciate you guys. Will update soon.
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You could be dealing with two separate problems here. The first is a vacuum leak, hence the P0171 and P0174 codes. Second you could have a misfire that's causing the roughness.
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I just let it run for about 45 mins. No check engine light. Run so much better but it has a very slight miss. The only thing at this point I did was clear the codes and tugged around on the pcv hoses and fittings. Fixing to go buy a fuel filter. Where is the filter located. Thanks guys.
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I put the fuel filter on. No change in the miss. I did as SKauber suggested and unplugged the coil packs one at a time and one of them didn't make any change in the rough idle so I'm thinking this might be the problem. Should I change all the plugs and coil packs or just the one I think might be bad? Drove the truck about 50 miles and the check engine light will not come back on.
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I put the fuel filter on. No change in the miss. I did as SKauber suggested and unplugged the coil packs one at a time and one of them didn't make any change in the rough idle so I'm thinking this might be the problem. Should I change all the plugs and coil packs or just the one I think might be bad? Drove the truck about 50 miles and the check engine light will not come back on.
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Appreciate the help CycleVin. I cant disagree with good advice. Definitely dont want to chase a ghost. Ill try swapping some things around and ill clean the maf. I bought a very basic code reader. Doesnt do much. I might try to borrow a better one from a friend. My wife would kill me if i bought the reader i wanted.