SPONSORED LINKS

Misfire on rough running engine. No CEL

Tiny
DENISLEE2015
  • MEMBER
  • 12 POSTS
And could fuel pressure cause one cylinder to misfire I'm seriously asking the head because most vehicles that I've had misfire they were random misfires when it was a fuel issue but like I said I'm not an expert I have no clue I'm just trying to figure it out I'll get a fuel pressure tester tomorrow I'm pretty sure its not a compression problem because it doesn't have any of the symptoms of a compression problem it has power loss of power I live in Pennsylvania and I can go up a pretty steep hill at 50 miles an hour and no problem I'm really thinking it's something stupid I was wondering if you could tell me what vacuum lines on there are supposed to have vacuum if I pull them off and put my finger on it I do not know much about vacuum lines but I know that I checked a couple of them and the lines coming from the valve covers that go it into a tea that go into the air breather they don't have any vacuum on them the EGR doesn't have vacuum when its idling but I'm not sure if that's supposed to the only ones that I seen that have vacuum or the brake booster and the one that goes from the throttle body to what I'm assuming is some fuel modulator
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
The lines going from the valve cover to air duct /breathers are not vacuum only the pcv is if you are good with a scanner freeze frame it and check your voltages if a sensor is bad can cause that also check grommets for air leaks. I'll send a vacuum diagram in next email because our site has changed and I can't do it on a reply.
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
See pic
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
APAC408
  • MEMBER
  • 118 POSTS
  • 2001 FORD ESCAPE
  • 150,000 MILES
I recently changed the spark plugs gaped them to specifications, changed the spark plug wires, the cap that goes to the spark plug wires and it still getting a misfire in cylinder 4. I'm thinking that it may not be getting fuel since that is the only cylinder with the misfire and also it isn't throwing out any other DTC
s besides the P0304 code.
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
DRCRANKNWRENCH
  • MECHANIC
  • 3,380 POSTS
You could check the fuel injector with a test light to see if it is firing and then pull the plug to see if it is getting wet with gas.
You can always check it for spark by pulling the plug and putting the plug into the boot and ground it out on the engine or chassis.
If all that works, you might want to test the compression on that cylinder and possibly the fuel pressure.
Autoo Zone and Advance Auto loan out tools for both tests.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
APAC408
  • MEMBER
  • 118 POSTS
Where are the fuel injectors located on this car is it underneath the air intake
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
DRCRANKNWRENCH
  • MECHANIC
  • 3,380 POSTS
If you look in line with each spark plug going down towards to head, you will see the injector in the head.
You can find the fuel rail if you can see the fuel regulator or where the fuel ine comes in. The fuel injectors will have this rail attached to the top of them as well as a positive and negative wire going into them, look for wiring harness.
These are the 2 wires you want to test with a test light to make sure the injector is completing the circuit and firing as they have a solenoid in them that moves to let gas in the cylinder.
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
APAC408
  • MEMBER
  • 118 POSTS
Ok so I did a compression check and said to say it but all cylinder came out fine except for cylinder number 4 no compression at all so what problems am I looking at for this. Head gasket piston rings?
Was this
answer
helpful?
Yes
No
+1
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
DRCRANKNWRENCH
  • MECHANIC
  • 3,380 POSTS
That is correct. You might have an igniton problem, unlikely, or carbon deposits on high mileage cars can melt holes through pistons. There are other reasons for mechanical damage such as oiling failure. However most likely is the head gasket.
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
KNIGHTSTOUR
  • MEMBER
  • 1 POST
  • 2001 FORD ESCAPE
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 154,000 MILES
I'm very certain it is not the coil since I swapped it with the number 1 coil and that cylinder is performing fine and number 2 is still misfiring with code P302.

However, the car was driving fairly well for about 5 miles before it started to misfire again after the coil swap but less often. I'm thinking it is the wire and or connector leading to the coil. My question(s) is (are):

What is the best way to diagnose this without mechanic/specialized diagnostic tools? I have a multimeter and a code reader but that's it.

Assuming it is the wire/connector and I can buy one (I see them online), where does the other end terminate? Do I just unwrap it fro the rest and trace it back?

Can I replace the whole wiring harness? If so what is its part number and where can I buy it?

Lastly could it still be something else? If so what?

Thanks for your help.
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Hi KnightsTour, Welcome to 2carpros and TY for the donation

P0302 A misfire in a specific cylinder should lead you to check the sparkpug, compression and injector for the that cylinder and probable causes of misfiring below

1. Defective spark plug
2. Inadequate spark/coil, defective spark plug wire.
3. Lack of compression
4. False air leakage.
5. Faulty fuel injectors.
6. Insufficient fuel pressure.
7. Contaminated fuel.
8. EGR valve that is leaking.
9. Oxygen sensors.
10. Throttle position sensor.
11. Idle air control valve.
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
APAC408
  • MEMBER
  • 118 POSTS
Okay so if I remember correctly the head that is closest to the engine would be the RH gasket and the one furthest away would be the LH gasket right
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
WIFEY HAS A 2003 W/ A 3.0L

THIS WAS AN ISSUE WITH HER'S THAT I WORKED ON HITHER AND YON, FOR MONTHS

I PROMISED MYSELF, I WOULD FIGURE OUT THE CYBER CONTROLLED CRITTER WITHOUT THE HELP OF A "PAY MECHANIC". TECHNOLOGY HAS WENT OVERBOARD.I'LL KEEP MY 2 JEEPS 35 AND 66 YEARS YOUNG

Reckon my symptoms are sorta the same as yours?

I had input from here also. Ended differently

Disregard all of this, if we're not on the same country road

Thought I'd sling it out there, for observation anyway. Open for any questions with mine. Hope it's simpler than mine!

I Went thru same deal w/ '03 Ford Escape 3.0 V-6

Repetitive, fast hesitations (stumbles), lasting 1-2 seconds, varied in how far the "sets" were apart, it was more evident climbing a incline, while slowly administering gas. Random or none on level ground. Every now and again at idle, but very seldom.

---No codes/ No CEL --- (cleaned 1st, and/ or replaced the following

New Plugs. Then "genuine plugs". Bah-Hum-bug, nothing wrong with the other new ones, I just installed!

Boots and springs

air filter

MAF

EGR

A new IAC for Sheets & Giggles!. Prevent-Maint. If for nothing else

Performed Mega Vacuum leak searches several times.

Fought with wife many times over situation, 2+ months!

I really hated taking off the "Plenum" so many times to access the other 3 cylinders

Each part seem to fix it for a day or two.I did not mind replacing the suggested parts, as I am all for "PM" and she's got 100,000 miles on her rig.

The final cure was #3 misfiring (lucked into the correct cylinder) I was gonna swap a new coil pack down the line, till it stopped

#3 was the ticket!

I had tried to get the Technical school to ride me with their portable machine---things did not work out, with their schedule.

I went to a salvage yard to get a used pack ($10) to swap around to figure out which was bad, then buy a new one, if the "donor pack" solved the problem.

So happened, the salvage yard guy had a machine, he found a stored code, it said #3 had misfired. My little code scanner could not tell me that.I think his was a "Snap On"

Runs perfect now, with the New $79 Coil Pack!

IF IT HAD NOT BEEN FOR THE STORED CODE, I WAS GONNA "ONE AT A TIME" SWAP THE COIL W/ THE 1ST EZ 3 TO FIND THE MISFIRING ONE. IF IT HAPPENED TO BE ONE UNDER THE "PLASTIC PLENUM"

THE PLAN WAS TO TAKE OFF AND REPLACE THE PLENUM ONE TIME ONLY!---BUT SWAP THE "3 GOOD" FRONT COIL PACKS TO THE REAR. THEN "TEST" THE 3 EZ FRONT ONES (RELOCATED FROM REAR) ONE AT A TIME WITH THE "DONOR COIL PACK"

THE STORED CODE MADE IT EZ ON ME, LOCATING THE BAD PACK

THE MEDIC
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
I SORTA RECKON I MISSED THAT YOU NOW MAY HAVE A COMPRESSION ISSUE. WHEN I CLICKED IN GOOGLE CHROME THE AUG 25ths POST WAS ON MY SCREEN AND I. DISREGARD MY BABBLING ABOVE

THE MEDIC
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
APAC408
  • MEMBER
  • 118 POSTS
Thanks for the info but like I said I did a compression test and cylinder number four had no compresssion in it at all the others were fine but back to my question the head gasket that I need to change which is the one closest to the front of the vehicle is the RH gasket right
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
FALCONE
  • MEMBER
  • 1 POST
1 min ago

FIRT TIME LIKE TWO YEARS AGO I CHANGED ALL GASKETS TOP AND LOWERS THE PROBLEM WAS FIXED AND THAT TIME MOTOR WAS UNSTABLE
TODAY IT IS ALMOST THE SAME PROBLEM I CHANGED GASKETS AND THE PROBLEM STILL BUT AND THEN I CHANGED ALL THE SET WIRE ON COILS THE PROBLEM WAS FIXED. 6 MONTH WITHOUT PROBLEMS WORKING GOOD ( AUTOZONE LIKE 40 DLL COST SETWIRE)
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
TIM949
  • MEMBER
  • 1 POST
  • 2001 FORD ESCAPE
  • 125,000 MILES
Engine light codes misfire in cylinder one.I have replaced plug coilpack no vacuume leak. Vehicle hesitates when starting from stopped position. Dont know what to do from here. Vehicle does this when warm.
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,757 POSTS
You have to eliminate all the common ignition issues first but this vehicle has a known problem with burning out the PCM drivers for the coils. IF that is confirmed, the solution is to replace all the coils and the PCM which will require programming.
Was this
answer
helpful?
Yes
No
-1
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
VOVIK86
  • MEMBER
  • 1 POST
  • 2001 FORD ESCAPE
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
Hello. I have had the check engine light on for 2-3 months. My car did not pass inspection and the mechanic told me there was a problem with my spark plugs. I replaced them and reset the battery but the engine light came back. Recently it got bad enough that I dont want to drive my car until the problem is fixed. The engine shakes a lot at 65mph or higher, the car cannot accelerate going uphill, and one point the car slowed down so much that I had push the gas pedal all the way down which bumped my engine rpm to 7000 just to maintain a constant speed of 50 mph.

Yesterday I scanned the OBD and got codes p0302 and p0303 which says that cylinders 2 and 3 are misfiring. I replaced my air, fuel filter, and battery about a year ago. The spark plugs are new. The wires are worn but I dont see any damage to them. All other components are original from when the car was bought (about 4 years ago from the previous owner). After close examination it seems that my car is slowly leaking transmission fluid. Any ideas on what the problem could be? What should I check next? I will change the transmission fluid as soon as I get a chance but I doubt that will solve the problem.

Thanks.
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check the sparkplug, compression and injector for those misfiring cylinders
Was this
answer
helpful?
Yes
No
Thursday, July 19th, 2018 AT 2:19 PM (Merged)

Please login or register to post a reply.

Related Engine Misfire Content

Intermittent Misfire
VIDEO
Intermittent Misfire
Instructional repair video
Misfire Random Code P0300
GUIDE
Misfire Random Code P0300
The world of automotive diagnostics can be complex, with numerous codes and potential issues to keep track of. One of the more common engine diagnostic codes is P0300, which...
VIEW MORE

Sponsored links