Poor MPG
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Senior User
Joined: Jan 2019
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its super simple.
1. Pop hood
2. Start engine
3. Unplug a 1 coil at a time
there will either be a distinct change in idle/smoothness/sound or there won’t. If there isn’t that one is dead
why didnt uou buy a 5.00 stethoscope from harbor freight instead of a screwdriver?
Also, had no idea HF stocked them! I'm going past one today so will pick one up. Thanks
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From: Media PA
Yes, you can unplug and replug at will while idling and it's just typical 12VDC, not like the plug wires between distributor and plugs where a leaky plug boot could light you up! Just pay attention and take your time, the little locking tabs on the COP plugs can be broken if they are forced off, make sure the tab is depressed before you try to pull the plug off the COP and you should be good.
. And if you find a plug that wasn't locked by a good tab that may be part of the issue and can be fixed.
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Senior User
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Yes, you can unplug and replug at will while idling and it's just typical 12VDC, not like the plug wires between distributor and plugs where a leaky plug boot could light you up! Just pay attention and take your time, the little locking tabs on the COP plugs can be broken if they are forced off, make sure the tab is depressed before you try to pull the plug off the COP and you should be good.
. And if you find a plug that wasn't locked by a good tab that may be part of the issue and can be fixed.Got myself a stethoscope so will get to listening to the injectors at some point next week though
Laughing Gas
Joined: Oct 2017
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From: ND
once the engine is warm, the plastic won't be so brittle and it won't be so cold under the hood to test the coils quick. can probably test all 10 coils in under 3min if you are slow
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I don't think I could even unscrew the first bolt clamping down the coil in 3 mins haha.
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From: Media PA
Well then, you are in luck! There won't be any need to unscrew any of those hold down bolts to do this misfire test, unless of course you do find a dead COP during the test. All of the electrical plugs are easily accessible without unbolting anything.
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Laughing Gas
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From: ND
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Still not got around to checking the plugs just yet - let me ask this though: 4.88 gears are on the horizon for me. If I kept the stock tires (to avoid a lift) I believe my RPM to be in the 3000 range for 65mph. Currently, my EX does 2000rpm @ 69mph.
Will my MPG worsen with this setup?
Will my MPG worsen with this setup?
Cargo Master
Joined: Aug 2012
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From: Kaufman TX
Typically with more gear you lose MPG on the highway because you need to turn more RPM for the same steady state power to the tire to maintain speed, your losses are in the engine friction, pumping more oil volume, etc. It isn't much though.
You should however see an improvement in efficiency on acceleration because of the torque multiplication, you need less throttle for the same acceleration so city style driving will have an improvement. Driving style and what your mix of city/highway is will determine your overall result.
You should however see an improvement in efficiency on acceleration because of the torque multiplication, you need less throttle for the same acceleration so city style driving will have an improvement. Driving style and what your mix of city/highway is will determine your overall result.
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Okay, tested the plugs.
Some were far easier to detect than others. On the passenger side, each gave a pretty definitive roughness to the engine. On the driver's side, it was more sound. What is labelled as plug #9, for instance, gave a barely perceptible difference in engine note and no difference in roughness.
Two of the plugs tabs DID BREAK in the process. I was a careful as can be but the damn things were so brittle (even though warm). Will zip-tie 'em until I get the plugs and COPs replaced (they're not Motorcraft... some unbranded nonsense).
Some were far easier to detect than others. On the passenger side, each gave a pretty definitive roughness to the engine. On the driver's side, it was more sound. What is labelled as plug #9, for instance, gave a barely perceptible difference in engine note and no difference in roughness.
Two of the plugs tabs DID BREAK in the process. I was a careful as can be but the damn things were so brittle (even though warm). Will zip-tie 'em until I get the plugs and COPs replaced (they're not Motorcraft... some unbranded nonsense).
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From: Media PA
Okay, tested the plugs.
Some were far easier to detect than others. On the passenger side, each gave a pretty definitive roughness to the engine. On the driver's side, it was more sound. What is labelled as plug #9, for instance, gave a barely perceptible difference in engine note and no difference in roughness.
Two of the plugs tabs DID BREAK in the process. I was a careful as can be but the damn things were so brittle (even though warm). How can I fix these to ensure they don't come loose?
Some were far easier to detect than others. On the passenger side, each gave a pretty definitive roughness to the engine. On the driver's side, it was more sound. What is labelled as plug #9, for instance, gave a barely perceptible difference in engine note and no difference in roughness.
Two of the plugs tabs DID BREAK in the process. I was a careful as can be but the damn things were so brittle (even though warm). How can I fix these to ensure they don't come loose?
For now you can secure the plugs with broken tabs with small cable ties and later when it's warmer out you can replace the plug ends with new ones, someone here has done it recently but I don't have the part numbers for those plugs in my notes. I'll try looking around to find the thread and part numbers.
Now why exactly are you contemplating 4.88 gears with stock (31.6") tires? That's a lot of gear, I ran my 4.88s with 32"s for two years before moving up to the 35"s that I wanted. My EX turned 2430 RPMs at 65 MPH with the 4.88s and 32"s, now with the 35" and effective 4.39 ratio it spins at 2230 RPMs at 65 MPH and 2400 at 70. My stock 3.73s and 31.6"s delivered 14-ish MPG daily driving with a 50/50 mix of city/highway and a best ever tank at 15.5 MPG, with the 4.88/32" combo it got 12.5 MPG on a 700 mile highway trip running solo at 65 MPH. BUT, the towing mileage increase from 6/7.5 MPG up to 9 MPG pulling the same 9.5K lbs TH over the same route and speeds.
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In that case I would order ten new plugs, ten new boots and two new COPs. Replace all the plugs and boots and swap out COP number nine, then see if performance and mileage improves. A fresh tuneup on a new rig is always a good way to establish a baseline. I'm very interested to see the old plugs when you change them out.
For now you can secure the plugs with broken tabs with small cable ties and later when it's warmer out you can replace the plug ends with new ones, someone here has done it recently but I don't have the part numbers for those plugs in my notes. I'll try looking around to find the thread and part numbers.
Now why exactly are you contemplating 4.88 gears with stock (31.6") tires? That's a lot of gear, I ran my 4.88s with 32"s for two years before moving up to the 35"s that wanted. My EX turned 2430 RPMs at 65 MPH with the 4.88s and 32"s, now with the 35" and effective 4.39 ratio it spins at 2230 RPMs at 65 MPH and 2400 at 70. My stock 3.73s and 31.6"s delivered 14-ish MPG daily driving with a 50/50 mix of city/highway and a best ever tank at 15.5 MPG, with the 4.88/32" combo it got 12.5 MPG on a 700 mile highway trip running solo at 65 MPH. BUT, the towing mileage increase from 6/7.5 MPG up to 9 MPG pulling the same 9.5K lbs TH over the same route and speeds.
In fact, are the Motorcraft boots labelled as so? I may actually have them, if not. I'll take a picture tomorrow.
Also, looking to get those gears based on advice (including yours actually!) in the other thread where I'm seeking to improve performance. Naturally, my MPG matters come first though
Thanks, as always, Sir!
Laughing Gas
Joined: Oct 2017
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From: ND
If you have a scanner capable of mode $06 then you could confirm your results, but there may be an obd code for it too since you said yours is obd2. I think even the obd1 ex’s might set a misfire code but I can’t remember for sure if mine did or not.
Otherwise we3zs has the right advice. And I can’t remember the part number but denso COPs are just relabeled motorcraft COPS for under 1/2 the price. I just removed all the denso stickers on mine and I couldn’t tell the difference between them and the 2 MC COPs that I bought
Otherwise we3zs has the right advice. And I can’t remember the part number but denso COPs are just relabeled motorcraft COPS for under 1/2 the price. I just removed all the denso stickers on mine and I couldn’t tell the difference between them and the 2 MC COPs that I bought