'00 V6/Auto w/ Misfire No CEL - EGR Ports???
03-15-2015, 10:17 AM
#1
1st Gear Member
Thread Starter
Join Date: Aug 2014
Location: New Jersey
Posts: 80
'00 V6/Auto w/ Misfire No CEL - EGR Ports???
This is a stock 3.8, automatic w/ 107k that I've been chasing misfires on for some time. I've replaced battery, plugs/wires/coil(Motorcraft), DPFE(Motorcraft), EGR valve, Fuel Filter, and lastly the HB. I have an engine shudder under load, mainly light throttle mostly prominent around 1500RPM. On interstate doing 50-65mph you feel the whole car shake. There's no CEL. When I bought this car last year it had a CEL for P0401 & 402 which was EGR flow errors. Replacing the DPFE eliminated the codes which never returned, but symptons persisted. Replaced EGR valve, same thing. I have pulled the plugs a few times and they were all clean, normal looking other then the #3 & 6 towards the back exhibiting the typical oil residue on the threads (PCV issue).
Car runs very smooth otherwise but does lack power under light loads. I noticed when cold outside and after car sits overnight, the engine cranks over for a few seconds before firing up. After driving it or when starting it in warmer weather overnight it tends to fire right up. Tested FP and it was good. I've also ran a vacuum test and it was normal 20-22 HG steady at idle and immediately zeros out and returns when doing 'snap' throttle. I know from researching that my car does have the 'faulty' valve cover on the dr side - 1/8 pinhole visible through the PCV hole. I have heard pinging in the warmer months under hard throttle tests. I have access to OBD II Live Data on my scanner and ran onboard monitor testing in Mode 06 and it shows 'cylinder events' active in a few cylinders but then all pass, hence why no CEL. I think I'm just about to the point of pulling the upper manifold off and taking a look at the EGR ports and cleaning them out. I haven't found much topics relating to these symptoms on all the Mustang forums I've visited but encountered numerous articles online with Windstars, F150 and E150 vehicles w/ the 3.8/4.2.
Anyone have any other thoughts?
Car runs very smooth otherwise but does lack power under light loads. I noticed when cold outside and after car sits overnight, the engine cranks over for a few seconds before firing up. After driving it or when starting it in warmer weather overnight it tends to fire right up. Tested FP and it was good. I've also ran a vacuum test and it was normal 20-22 HG steady at idle and immediately zeros out and returns when doing 'snap' throttle. I know from researching that my car does have the 'faulty' valve cover on the dr side - 1/8 pinhole visible through the PCV hole. I have heard pinging in the warmer months under hard throttle tests. I have access to OBD II Live Data on my scanner and ran onboard monitor testing in Mode 06 and it shows 'cylinder events' active in a few cylinders but then all pass, hence why no CEL. I think I'm just about to the point of pulling the upper manifold off and taking a look at the EGR ports and cleaning them out. I haven't found much topics relating to these symptoms on all the Mustang forums I've visited but encountered numerous articles online with Windstars, F150 and E150 vehicles w/ the 3.8/4.2.
Anyone have any other thoughts?
05-22-2015, 10:51 AM
#2
1st Gear Member
Thread Starter
Join Date: Aug 2014
Location: New Jersey
Posts: 80
Just re-posting a follow up and bringing this back.
In recent months this year, I replaced the d/s valve cover baffle w/ the 01+ style plus a new motorcraft PCV valve. I also pulled the upper intake manifold off and cleaned it out and also cleaned out the EGR ports. None of them were blocked btw. The upper intake had some sludge build up mainly in the 1/2, 3/4 runners. The 5/6 runners were clean, BUT had a nice fresh film of oil on them which I suspect was the faulty VC baffle allowing too much oil through those runners.
I also replaced the exhaust manifolds, it turns out mine had some small leaks around the primary flanges where the welds had slight cracks. The rest of the manifolds looked ok. I used Dorman replacements w/ new gaskets.
After doing the above, I noticed the car seems more responsive then before, BUT I still have:
-Rough cold start (cycling the key doesn't help and had already run FP test and was normal)
-What I've also noticed now, when I start the car up - if I fully press the brake pedal and then release it, upon release the engine stumbles a bit. This is more noticeable when engine is still cold, you can feel the whole car shake a bit. It will do it when fully warm but very subtle <THINKING VAC LEAK HERE?
-Shudder/miss at most noticeable when fully warmed up at idle and when light load btwn 1300-1800RPM. I can replicate this shake in P, N and just driving around in that RPM range.
-I had run EGR systems tests on the car a few months back and they all passed. The only thing is, the car may have not been fully warmed up/driven right before. I may run these tests again with the motor nice and 'hot' to see if anything changes.
-I've run a few tanks of 93 recently and one of my last tanks threw in some Gumout Regane. Can't say I really noticed a change. Last tank full w/ that Regane I avg'd 22mpg, mixed.
-Replaced plugs again, and wires. When I pulled the plugs they were all dry/normal specifically the #5&6 which originally had shown traces of oil around the threads (original PCV baffle)
No codes - stored or pending. I've done some more datalogging, maybe someone here is willing to take a look at my logs to see if something appears off?
My scanner will read components testing (MODE $06) and it picks up a misfire in #6, but very low. Also in ID$12 Differential Pressure Hose downstream comes up 'FAIL'. The DPFE hoses are fine and clear of any blockage. The DPFE is a new MC unit w/ less than 7k miles...what's up with that?
Any further thoughts much appreciated!
In recent months this year, I replaced the d/s valve cover baffle w/ the 01+ style plus a new motorcraft PCV valve. I also pulled the upper intake manifold off and cleaned it out and also cleaned out the EGR ports. None of them were blocked btw. The upper intake had some sludge build up mainly in the 1/2, 3/4 runners. The 5/6 runners were clean, BUT had a nice fresh film of oil on them which I suspect was the faulty VC baffle allowing too much oil through those runners.
I also replaced the exhaust manifolds, it turns out mine had some small leaks around the primary flanges where the welds had slight cracks. The rest of the manifolds looked ok. I used Dorman replacements w/ new gaskets.
After doing the above, I noticed the car seems more responsive then before, BUT I still have:
-Rough cold start (cycling the key doesn't help and had already run FP test and was normal)
-What I've also noticed now, when I start the car up - if I fully press the brake pedal and then release it, upon release the engine stumbles a bit. This is more noticeable when engine is still cold, you can feel the whole car shake a bit. It will do it when fully warm but very subtle <THINKING VAC LEAK HERE?
-Shudder/miss at most noticeable when fully warmed up at idle and when light load btwn 1300-1800RPM. I can replicate this shake in P, N and just driving around in that RPM range.
-I had run EGR systems tests on the car a few months back and they all passed. The only thing is, the car may have not been fully warmed up/driven right before. I may run these tests again with the motor nice and 'hot' to see if anything changes.
-I've run a few tanks of 93 recently and one of my last tanks threw in some Gumout Regane. Can't say I really noticed a change. Last tank full w/ that Regane I avg'd 22mpg, mixed.
-Replaced plugs again, and wires. When I pulled the plugs they were all dry/normal specifically the #5&6 which originally had shown traces of oil around the threads (original PCV baffle)
No codes - stored or pending. I've done some more datalogging, maybe someone here is willing to take a look at my logs to see if something appears off?
My scanner will read components testing (MODE $06) and it picks up a misfire in #6, but very low. Also in ID$12 Differential Pressure Hose downstream comes up 'FAIL'. The DPFE hoses are fine and clear of any blockage. The DPFE is a new MC unit w/ less than 7k miles...what's up with that?
Any further thoughts much appreciated!
05-22-2015, 11:10 AM
#4
3rd Gear Member
Join Date: Apr 2011
Location: Wisconsin
Posts: 917
If a car is running rough, it will almost always show up in the plugs. What colour are they? Do all the plugs look the same?
You mentioned oil on several, does it run better when you replace the plugs or clean them? Are you using the correct plugs? Has the engine been modified? Is there a chance one of your cats is clogged? You can usually see that with a vacuum gauge. If the car shakes at 60 mph, sounds like 2 cylinders are not firing, or the timing is jumping around a lot. Have you looked at the timing with a timing light? Btw, you can clip the timing light sensor on all of the wires one at a time to see if they are firing intermittently.
You mentioned oil on several, does it run better when you replace the plugs or clean them? Are you using the correct plugs? Has the engine been modified? Is there a chance one of your cats is clogged? You can usually see that with a vacuum gauge. If the car shakes at 60 mph, sounds like 2 cylinders are not firing, or the timing is jumping around a lot. Have you looked at the timing with a timing light? Btw, you can clip the timing light sensor on all of the wires one at a time to see if they are firing intermittently.
05-22-2015, 02:10 PM
#5
1st Gear Member
Thread Starter
Join Date: Aug 2014
Location: New Jersey
Posts: 80
Engine is 100% stock, down to a replacement MC paper air filter. Plugs were fine, and I used MC double plats which are OE replacements. The 2 back plugs, #3&6 were the only ones with oil on them prior to me changing the driver's side valve cover baffle. I got my numbers mixed up in previous post.
Since I changed the baffle out, I've pulled the plugs once after a few hundred miles or so and they were all bone dry and looked fine, meaning that the valve cover fix worked.
Not ruling out the cats, but engine vacuum was perfect when I tested it. I didn't bother with timing light since my OBD II scanner shows ignition timing on it and it looks to be ok, meaning it's not erradic and jumping everywhere.
The wires were replaced with Motorcraft ones last year. I ended up replacing them again with Napa premium(Belden) along with fresh Motorcraft platinum spark plugs last month. The coil was already replaced last year with a Motorcraft unit.
Since I changed the baffle out, I've pulled the plugs once after a few hundred miles or so and they were all bone dry and looked fine, meaning that the valve cover fix worked.
Not ruling out the cats, but engine vacuum was perfect when I tested it. I didn't bother with timing light since my OBD II scanner shows ignition timing on it and it looks to be ok, meaning it's not erradic and jumping everywhere.
The wires were replaced with Motorcraft ones last year. I ended up replacing them again with Napa premium(Belden) along with fresh Motorcraft platinum spark plugs last month. The coil was already replaced last year with a Motorcraft unit.