2002 v8 4.6 Ford Explorer will idle great but will barely run when in drive

[rambo3000]

About a year ago I had a rough idle but found out I had a bad elbow going to the throttle body, I fixed it and it ran great.

For about a month it had been running rough again but the idle was ok, it was like it would jump while driving, Hard to explain but when pushing the gas its like it would miss or stutter.

Then one day it just would not drive past 5 MPH and then I was able to pull into a parking lot and it had to be towed home because was not running right.

I took to auto zone and they said the codes said it was misfiring on about all cylinders but had a friend test it and he said it was only misfiring on cylinder one.

Here is what I have done so far.

• I have cleaned the MAF sensor and AIC valve and replace the AIC valve,
• Checked all the cables for cracks or leaks
• cleaned spark plug holes, cleaned coil boots and put new spark plugs in
• put new fuel filter in
• I ordered 8 new coils that will be here Tuesday

after doing the above the car is idling great and starts right up but when I put in drive and push the gas goes very slow.

I have been watching videos and reading every thing online that I can but have no idea other then the misfires auto zone told me.

It does have a small oil leak but nothing major.

Any help or ideas would be great, I can't get any codes because I'm not able to drive it.

 

[SyberTiger]

Uh oh....

Another catalytic converter plugged up....

 

[ROBinGa]

Yeah this is going viral....

 

[rambo3000]

why is that

 

[ROBinGa]

My Explorer 4.6 is having these same symptoms and so was another forum member. We have been discussing in another thread in the past few days. The one on Help no engine Power. Before you open the coils check to see if you have the clogged cat and maybe you can return the coils if so. The complete cat assembly is around $450-$500. My local mechanic shop quoted me $720 for the new cat and install and that's what I am doing. That's is if they perform their test and verify it is the plugged cat which I have to have them tow in to check. I am gonna go ahead and bite the bullet and not drill any holes. Beating my cats with hammer did not free up any restriction.

 

[shane10]

Check for any exhaust leaks, though it doesn't sound like that's your problem given no O2 codes shown.
I had the same symptoms as you, would start and idle fine, but in drive would stutter/surge, wouldn't go past 10MPH unless floored.
Found a leak at the flange gasket between the cat and exhaust manifold, was just a loose bolt once tightened it was running better than ever. It should have been pretty obvious but the noise was pretty minimal and not until I opened up the hood and got close could I really hear it.
BTW symptoms caused by air entering the system close to the O2 sensor, causing car to run rich/bogged down.

 

[rambo3000]

Thanks everyone,

ROBinGa

I think we are having the same problem, I had some coolant leaking into cyliyer number 5 a while back when I had the plugs changed but they told me it was no big deal and it would cost 1000 dollars to fix it so said no. I have just decide to buy a new truck because that old girl looks like she is just going to cost more time and more money but would like to get it running.

I saw your other post and was wondering where to drill in the cats because there is the driver side, passenger side and the middle from what I can see.

Shane10

Where would be the best place to tighten the bolt under the car or above.

Thanks again everyone.

I will give you an update soon.

 

[rambo3000]

Also reading online allot of people are saying just take the cat up and use a rob and smash every thing out of it and then put it back on.

 

[imp]

My Explorer 4.6 is having these same symptoms and so was another forum member. We have been discussing in another thread in the past few days. The one on Help no engine Power. Before you open the coils check to see if you have the clogged cat and maybe you can return the coils if so. The complete cat assembly is around $450-$500. My local mechanic shop quoted me $720 for the new cat and install and that's what I am doing. That's is if they perform their test and verify it is the plugged cat which I have to have them tow in to check. I am gonna go ahead and bite the bullet and not drill any holes. Beating my cats with hammer did not free up any restriction.

@ROBinGa
But doing so seems to have cured mine. My behavior was directed to the RH cat due to recurring code (1) indicating bad O2 sensor, or wiring. Neither was the case, so directed anger at the offending cat. However, mine was obviously not clogged or anywhere near it; the vehicle ran fine all along, and continues to do so now. 2004 4.0L Flex. Nom DTCs! Hurray! imp

 

[rambo3000]

Hello Everyone just an update.

I got a code machine from auto zone today and put it in the explorer, got 12 codes bunch for miss fires and these

p1131
p0113
p1131
p1401
p0102

I also put all new coil packs in today hoping it would work but pretty much the same thing so said its do or die and drilled 4 1/4 holes in the middle cat and bang it looks like it was the problem just like everyone has said along. So looks like I need new cats all along.

 

[imp]

@rambo3000
P1131 indicates faulty O2 sensor, upstream, right bank, the important one. If it were me, I would replace both upstream sensors, depending on how many miles are on them. imp

 

[rambo3000]

Thanks 150,000 miles on it

 

[rambo3000]

Also those are the ones on the bottom under the car right?

Thanks again

 

[imp]

Also those are the ones on the bottom under the car right?

Thanks again

@rambo3000
There is a catalytic converter for each bank, 2 cats. Each cat has an O2 sensor threaded into a bung, one where the exhaust pipe comes down from the engine, another at the other, "downstream" end of the cat. Ford numbers them 1-1, 1-2, 2-1, and 2-2. The first digit is the cylinder bank, 1 being right side (passenger). Second digit is the sensor location, 1 being toward engine, 2 being far end of cat. Your P1131 indicates faulty operation of the 1-1 Oxygen Sensor, right bank, closest to the engine. imp

 

[rambo3000]

Thanks IMP

I just ordered two of them, so do you think that I should have waited to drill holes in the cat before replacing them

 

[imp]

Thanks IMP

I just ordered two of them, so do you think that I should have waited to drill holes in the cat before replacing them

@rambo3000
Nah, if you replace the cats, they likely do not come with sensors, anyway. Be aware, that the upstream and downstream sensors are NOT alike, though. Don't mix them up. I doubt the holes will make much difference. Compared to the cost of cats, 2 sensors ain't much dough. imp

 

[ROBinGa]

My shop towed the Explorer and did diagnosis and said backpressure indicated clogged Catalytic converter. They are replacing the whole cat assembly as I just don't think I want to tackle this one in my residential garage space with ramps. Will be less than $800 in my case

Advice to anyone else reading this. Don't start throwing parts at your 4.6 if it starts running as describded above where it idles normally but won't rev above 2,000 rpm. Too many examples if this being clogged cats. Get it tested. Now you do need to find out what clogged the cat to make sure new ones don't get clogged too. In my case I think it was having coolant get in through the intake manifold failure point. I have solved that with new intake manifold. But I also may have spent money on 4 coil over plug units that could have been ok.

 

[rambo3000]

Today I had my rear cat replaced for 200 dollars and my explorer is running great. Allot cheaper then replace all 3 of them. I still think every thing else that I did was good and at the end of the day it will just make it run better in the long run.

 

[ROBinGa]

That's great news!

 

[imp]

Today I had my rear cat replaced for 200 dollars and my explorer is running great. Allot cheaper then replace all 3 of them. I still think every thing else that I did was good and at the end of the day it will just make it run better in the long run.

@rambo3000
4.6 uses 3 cats?
IMP