[boxerz]

2001 3.8L V6 Mustang with 116,000 miles, Manual. Only mods are cold air intake.

Recently, I took the car on the highway with some friends and I don't normally ever let it get to 4000 RPMs but I was accelerating hard and my car backfired when I hit 4000 RPMs in third gear. A few minutes later, my check engine light came on P0301 - Cylinder 1 Misfire. I've had that same error code come on for the last 6 months. I changed out all the spark plugs and wires 2,000 miles ago gapped them between .052 and .056. I tried to gap them all at .052 but I don't have a tool, I just use the cheap measuring tool from Autozone so they are all about .052 to .054 mainly, I don't know if this small difference would cause a huge difference..

I recently did an oil change, I had the mechanic look at the ignition coil and he ran all his tests and said nothing was wrong with it.

So yesterday I changed the o2 sensor on the driver's side since I was told by my friend that the fuel/air ratio might be wrong. I didn't get a chance to do the passenger's side but I will today when I get it on the lift. I drove it again after the o2 sensor change and pushed it to 4000RPMs at 3rd gear and it backfired again. I've put fuel injector cleaners on a regular basis. I mainly do city driving up to 30mph since I live on military installation so not many instances where I can even get to third gear at that RPM.

[mcqueen]

The .052-.054 gap isn't the issue. Technically the spark plugs should be gapped to .054 but I usually gap mine to .052. When was the last time your fuel filter was changed? Cats in good condition? Is your car tuned? Timing good?

[Tang Stang]

I'm guessing the cold air intake is using an oiled air filter? When was the last time you cleaned the MAF?

[boxerz]

I bought this car from carmax at 70k miles in the 3 years Ive had it I put about 46k miles, majority of it in the first 2 years. This is my first car I bought and am still learning how to do the maintenance besides the oil and air filter changes. I'm learning via Haynes manual, friends and the internet

Originally Posted by mcqueen The .052-.054 gap isn't the issue. Technically the spark plugs should be gapped to .054 but I usually gap mine to .052. When was the last time your fuel filter was changed? Cats in good condition? Is your car tuned? Timing good?

For the fuel filter change, I have not done one and it's way overdue. I think it's every 30k miles? That will be my next project. I can't tell if cats are in good condition, I have no prior experience with car maintenance nor was taught by anyone. My car is not tuned. Timing, I sent it to the mechanic last night to look at the distributor cap and timing but he said it's a coil pack(ignition coil supposedly). I looked at the Haynes manual and the distributor cap and rotor is for V8s I believe.. I don't know how to check timing, I guess that maybe an electrical thing which I try to stay clear of.

Originally Posted by Tang Stang I'm guessing the cold air intake is using an oiled air filter? When was the last time you cleaned the MAF?

I recently bought the CAI about 1k miles ago its still a new CAI. I have not re-oiled it yet. I have never cleaned the MAF, I did not know I was supposed to.
This is the CAI I bought from american muscle, standard cheap one.
Mustang V6 Cold Air Intake Kit at AmericanMuscle.com - Free Shipping!



So that leaves me with thinking Fuel Injector for Cylinder 1, Fuel Pump, Fuel Filter, O2 sensor on passenger side.
I am changing O2 sensor for passenger side today. Fuel Filter will be this weekend hopefully.
The car studders in hard acceleration as in its not very smooth in third-fifth gear at 1900 to 2500 RPMs but it's a lot smoother in the higher RPMs. I am guessing because it's just the gear ratios? I have no clue
I get only 20-21mpg but mainly I'm driving on base majority of the time and highway when I do go off base.

[walt1120]

No, he was saying that oiled air filters like K&N are known for sometimes coating the MAF sensor in a little oil, that comes from the filter.

But definitely change you fuel filter. just buy a fuel line disconnect tool from autozone or something and it takes about 10mins to do. if you have any trouble watch the video on Americanmuscle...Ford Motorcraft Mustang OEM Fuel Filter (98-04) at AmericanMuscle.com - Free Shipping! (click on the installation tab)

[boxerz]

Originally Posted by walt1120 No, he was saying that oiled air filters like K&N are known for sometimes coating the MAF sensor in a little oil, that comes from the filter. But definitely change you fuel filter. just buy a fuel line disconnect tool from autozone or something and it takes about 10mins to do. if you have any trouble watch the video on Americanmuscle...Ford Motorcraft Mustang OEM Fuel Filter (98-04) at AmericanMuscle.com - Free Shipping! (click on the installation tab)

Will do, thanks for the link!
I have access to lifts since every base seems to have an Auto Hobby Shop that we can use a stall for $5/hr. Unfortunately I just filled her up so I'll wait til I get a bit low on gas and read up on my Haynes manual as well.

[walt1120]

Originally Posted by boxerz Will do, thanks for the link! I have access to lifts since every base seems to have an Auto Hobby Shop that we can use a stall for $5/hr. Unfortunately I just filled her up so I'll wait til I get a bit low on gas and read up on my Haynes manual as well.

its ok even if it has a full tank, all you need to do is turn off your fuel pump switch and run the car until it dies. that will empty the gas lines of MOST of the gas but not all so still be careful. its all in the video

[Tang Stang]

Originally Posted by walt1120 No, he was saying that oiled air filters like K&N are known for sometimes coating the MAF sensor in a little oil, that comes from the filter.

Exactly, which throws off the A/F ratio, as well as the load values seen by the EEC, which then throws off the ignition timing. Clean your MAF.

[mcqueen]

Originally Posted by boxerz For the fuel filter change, I have not done one and it's way overdue. I think it's every 30k miles? That will be my next project. I can't tell if cats are in good condition, I have no prior experience with car maintenance nor was taught by anyone. My car is not tuned. Timing, I sent it to the mechanic last night to look at the distributor cap and timing but he said it's a coil pack(ignition coil supposedly). I looked at the Haynes manual and the distributor cap and rotor is for V8s I believe.. I don't know how to check timing, I guess that maybe an electrical thing which I try to stay clear of.

Fuel filter is a real simple job. Demon is supposed to be getting pics for me when he does his (I'm too lazy to go get my own pics) and I'll be doing a write-up for my site but if you need help just let me know and I'll walk you through it. Also, distributors were last used in the 95 Mustangs. In 96 the V6 got coil packs and the V8s went to coil on plug (COP) setups. And if you're not tuned then I assume you don't have a tuner and therefore haven't messed with your timing so it should be fine.

[Mr. Red Pony]

Seems strange if its only 3rd gear..

[boxerz]

Originally Posted by Mr. Red Pony Seems strange if its only 3rd gear..

I spoke to my mechanic and he said try easing into 3rd gear slowly to a higher RPM. I eased into it slowly up to 4k and it did not back fire but when I do accelerate hard on 3rd gear it will backfire. It did it at 3.5k for the first time.

I was hitting about 4k RPMs at 1st and 2nd to see if it would happen at those gears then I eased it slowly into 4k at 3rd with no backfire. So the difference is how hard I step on the pedal. (this is all before 2nd o2 sensor change)

I changed my o2 sensor (both) and now have disconnected the negative battery terminal for 30 mins. I'm about to go re-connect and re-train the computer (IAC?). My supervisor said that would reset my settings so that it can adjust to the new o2 sensors just in case the old ones were worn.



(TOTAL SEPARATE SUBJECT - BRAKES)
I also installed new rear brake pads and fixed the squeal which was actually the front passenger side brake but that was a bad installation on my part.

a separate issue here (1week ago) but previously I had 2 new front rotors and the back ones resurfaced with all new brake pads. I didn't pump my brakes and then engaged my e-brake then disengaged it. Well I drove on the highway and heard a loud scream from the wheels and it was my passenger rear brake engaged and it was extremely hot and smelly. I put it on the lift and replaced the pads to find a hairline fracture on the brand new brake pad since the e-brake was still engaged when it was actually down all the way because I didn't pump my brakes prior.

So I replaced the rear pads and pumped the brakes while the car was off, engaged the e-brake, disengaged the car, pushed the car from the outside to make sure the e-brake was fully disengaged. I went to 'bed' my brakes doing the 60mph to 10mph stop and go while continuing to move.

When I got out of the car, the front brakes were cool, the driver side was warm and the passenger side was hot! Installation was correct but the same passenger rear brake is running hot. I'm thinking a new caliper may be needed? Is there some way to calibrate the break itself?

[ag11hockey]

sounds like a fuel issue then if its only under a heavy load. will it do it in any other gear like high rpms in first or second? or try bogging the car down in like 4th or 5th going like 30 and hit the gas hard and see if it does it. idk just throwing ideas out there...

[ag11hockey]

and to answer your second issue. yes its the caliper. replace it.

[boxerz]

Originally Posted by ag11hockey sounds like a fuel issue then if its only under a heavy load. will it do it in any other gear like high rpms in first or second? or try bogging the car down in like 4th or 5th going like 30 and hit the gas hard and see if it does it. idk just throwing ideas out there...

I think you are right. I am trying to take Wednesday off so I can go to the Auto Hobby shop which I'll have 8+ hours of lift time if needed which shouldn't be needed.

I plan on doing the fuel filter change, clean MAF with electrical cleaner, clean everything else with carb cleaner. I picked those up at autozone yesterday. I hit 3rd gear at 4k RPMs again on the freeway and it multipled backfired for the first time with a continuous back to back backfire. In 4th gear if I push it to 3k RPMs hard it will flash the check engine light. In my overdrive gear, if I fall under 70mph (2k RPMs), car will bog like crazy and decelerate.

As far as the 100k tune up stuff, I need to get some type of oil for the CAI, do a radiator flush, replace steering wheel fluid. Gotta run..

[boxerz]

I changed my fuel filter and coolant fluid. Runs a lot smoother now, the coolant did not need changing but the fuel filter was way overdue according to my friend who has 2 mustangs. Since the summer is coming and we're in NorCal where it's still warm for the most part, we did a 20% coolant / 80% distilled water mix or something to that effect. Mainly because I was dumb enough to buy only 1 jug of 50/50 coolant.

I accelerated hard into 2nd gear and it did backfire for the first time in 2nd gear. So the conclusion is: hard acceleration + bad something = backfire.

It's the bad something which is still a mystery. Timing? Spark plug? Fuel injector?

I still get the P0301 Cylinder 1 misfire if I hard accelerate in fourth gear. Spark plugs and wires all replaced and gapped not too long ago..

So I'm thinking of replacing fuel injector 1 which is another new project to learn. I was told timing could be an issue but I never tuned my car..

Yet to still clean the MAF, didn't have time yet, had to work on my downed Suzuki SV650S

[boxerz]

Originally Posted by boxerz I changed my fuel filter and coolant fluid. Runs a lot smoother now, the coolant did not need changing but the fuel filter was way overdue according to my friend who has 2 mustangs. Since the summer is coming and we're in NorCal where it's still warm for the most part, we did a 20% coolant / 80% distilled water mix or something to that effect. Mainly because I was dumb enough to buy only 1 jug of 50/50 coolant. I accelerated hard into 2nd gear and it did backfire for the first time in 2nd gear. So the conclusion is: hard acceleration + bad something = backfire. It's the bad something which is still a mystery. Timing? Spark plug? Fuel injector? I still get the P0301 Cylinder 1 misfire if I hard accelerate in fourth gear. Spark plugs and wires all replaced and gapped not too long ago.. So I'm thinking of replacing fuel injector 1 which is another new project to learn. I was told timing could be an issue but I never tuned my car.. Yet to still clean the MAF, didn't have time yet, had to work on my downed Suzuki SV650S

Well after cleaning the MAF, putting a new clutch, and replacing the back o2 sensors, the problem still exists.

I am thinking of changing the coil pack. This looks like it is the same as the OEM one on my mustang. I am not looking for a performance part but I just came up on this. 2001-04 Mustang 3.8L V6 Screamin' Deamon Coil Pack by Performance Distributors at LRS - Same Day Shipping!

A neighbor said Fords are known for bad distributor/coil pack and since the plugs and wires were replaced, I figured this is the last part of the electrical situation I could look into before looking into fuel injectors. Also, this looks like a cheaper route then changing out my fuel injector(s).

Is this a simple bolt off bolt on replacement?
Air + Fuel + Spark..