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HDGENE
HDGENE, Ford Senior Master/Diesel/Trans
Category: Ford
Satisfied Customers: 4847
Experience:  25 years Auto experience, Ford ,GM, Chrysler, Asian & European
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I have a 2004 t bird sometimes on start up it misses badly

Customer Question

I have a 2004 t bird sometimes on start up it misses badly but clears up shortly never shows check engine light or sets code what could cause this problem
Submitted: 1 year ago.
Category: Ford
Expert:  Randall C replied 1 year ago.

Hello, when this happens is it on cold start or hot restart?

Customer: replied 1 year ago.
It happens on warm restart
Expert:  Randall C replied 1 year ago.

Unsure on that one right off, I will opt out, another expert should be along soon to help

Expert:  HDGENE replied 1 year ago.

Hello, sound slike you may have a fuel injector leaking down into the cylinder and causing a misfire until the excess fuel in the cylinder(s) burn off. You would have to install a fuel pressure gauge and check for proper fuel pressure and see if it leakd down after sitting for a short period of time, if so, you would have to pull the spark plugs to see which one(s) are wet with fuel and replace the affected injectors if not all 8 if you opted to do so.

Customer: replied 1 year ago.
Ok I will run fuel pressure check what about heat sensor that puts injected in a fail mode read something about cuts out some injectors for cool down it only has the miss sometimes not every tlme
Expert:  HDGENE replied 1 year ago.

That would be if you had a coolant leak and the engine was overheating it would put it in a failsafe mode but cancelling injectors as it runs so the compressed air in the cylinders would help cool the engine down

Customer: replied 1 year ago.
But what lf the sensor that puts in limp mode is bad it may be a month or so before it falls just can't figure it out
Expert:  HDGENE replied 1 year ago.

Lots of thing can put it in limp mode and it wouldnt affect it at idle. Only while driving, the check engine light would be on and store a code when in limp mode as well as store freeze frame data to know why it is in limp mode. These are known for fuel injector issues. I would concentrate on what you can verify by testing verses what if's.

Customer: replied 1 year ago.
Ok I will check fuel pressure today it just seems if it was an injector it would happen every time
Expert:  HDGENE replied 1 year ago.

Usually when sitting for a period of time and depending on how much it leaks down if it does.

Customer: replied 1 year ago.
Ok fuel pressure should be 50 or 60
Expert:  HDGENE replied 1 year ago.

Yes close to 60 psi key on engine off and hold steady not bleed down. Important to do this test when the concern occurs as well.

Customer: replied 1 year ago.
Ok will let you know
Expert:  HDGENE replied 1 year ago.

no problem.

Customer: replied 1 year ago.
50 lbs at fuel rail and no leak down
Expert:  HDGENE replied 1 year ago.

Ok so then at this time the injectors look to be ok. Does it happen now with the gauge hooked up the hard start/running rough? No codes are stored and it passes a Key On Engine Off & Key On Engine Running test with a scan tool?

Expert:  HDGENE replied 1 year ago.

Does the vehicle sit for long periods of time/fuel quality?

Customer: replied 1 year ago.
Gage dropped 10 lbs
Expert:  HDGENE replied 1 year ago.

I thought you said it had no leakdown?

Customer: replied 1 year ago.
After 30 mins leak down 10lbs, that's all it has lost w/key off
Expert:  HDGENE replied 1 year ago.

Ok thats normal to see after a period of time, main thing is not a sudden leak down/continual leak.

Customer: replied 1 year ago.
Ok no rough or missing engine fuel pressure never went below 36 what next hooked up scan tool no codes set
Expert:  HDGENE replied 1 year ago.

Check mode 6 data with the scan tool to identify a msfire that isnt triggering a diagnostic trouble code to know what cylinder(s) may be affected. Possible ignition coil issue, oil in spark plug tube from a leaking valve cover gasket.Causing the coil to short or misfire at times when hot on restart.

Customer: replied 1 year ago.
Ok I will work on it again tomorrow
Expert:  HDGENE replied 1 year ago.

Thats the only other common issue, leaking injectors and an oil leak from the valve covers into the spark plug tubes which would require replacement of the valve cover gaskets and any coils that are contaminated. Inspect spark plug gap and wear and replace if needed

Expert:  HDGENE replied 1 year ago.

Hello, do you need more help of this concern?

Customer: replied 1 year ago.
Replaced spark plugs with e3 supposed to be the best. No oil on cop or rubes I am done went through checks you recommend
Expert:  HDGENE replied 1 year ago.

Ok did the old spark plugs look worn? Only other thing to check for a random misfire is OBDII Mode 6 data which tells you what cylinder if any shows a misfire below the threshold of setting a check engine light 0-20 %

Customer: replied 1 year ago.
Spark plugs were in fair shape had 5000 miles on them,
Customer: replied 1 year ago.
Thanks a lot. I just needed one time service you were very knowledgeable. And helpful
Expert:  HDGENE replied 1 year ago.

No problem, thats the only thing left to test, you would need a higher end scan tool to look at mode 6 data

Expert:  HDGENE replied 1 year ago.

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