Engine misfires, particularly when trying to accelerate

In no particular order.

Dirty spark plugs causing a misfire.
Tickover too low.
Dirty fuel injectors
Worn engine mounts rocking the engine.
It's a diesel engine (if it is).

'year make model' in all questions please.

fix misfire [s]

change the ignition coil pack common problem p0303 means cylinder 3 misfire and the coil pack are know to go out on these particular models

well if engine is ok. No year, no engine stated, wow. !!!
misfire is bad combustion. (gas usa cars are my answers)

1. never did a TUNEUP this decade? 60,000 miles tunes.?
2. bad spark first.
3. bad fueling next too rich causes misfire. lean bogs.
4. misfire shakes engine hard, is it .
5. does it misfire parked just racing engine?
6. cause are many over 50, but if engine good way less, so what can it be (we do tests no Gue$$) bad spark plugs, leaking injectors execessive fuel pressure, bad TPS, sensor. map sensor issues, (even clogged) and others. no engine stated makes waxing smart, hard, way to hard so i quit here.

either you have a faulty gas pump, one or more spark plugs or cables ar going bad or nrrd to br replace, could be a vacuum leak too, yourcar have the check engine light on? if so, need to know what code the will help you a lot.

mass air and tps would be 2 most common causes.

Try to determine if a particular cylinder or cylinders are misfiring. If it is definitely a certain cylinder, look for a bad coil pack on plug bad and replace as indicated by the misfire codes found in the computer.

I would be surprised that the misfire was not detected by the computer if you feel it happening.

Good luck on this repair.

apply brake and accelerate engine while vehicle is standing still, you need to apply brake hard, DO NOT do this for a period of more than 1 minute or you will be putting alot of stress on your transmission. you will be trying to set off the "check engine" warning lamp or the "service engine soon" warning lamp, and get a misfire failure code, after code sets on your vehicle computer, get it scanned it will tell you which engine cylinder is misfiring ie "P0301= cylinder #1 misfire" then check out spark plug, spark plug wire and ignition coil. one of them is probably causing this.

Sounds like misfire... Did the 'Check Engine' Light come ON? Whenever the 'CHECK ENGINE' light comes on, the ECU (Engine Control Unit) sets a Diagnostic Trouble Code (DTC). These codes identify the particular engine management system which caused the light to come on.
You'll need to use/find an OBDII (On-Board Diagnostic) Scanner to retrieve any code which have been stored in the ECU computer. Afterward, we might be able to help you DIAGNOSE and perhaps eventually fix the problem.

here's the scoop. There is a TSB that addresses this issue.
First, replace the spark plugs.
Next, replace all 6 COPS, coil on plug. You have to because they feed back into the PCM, Powertrain Control Module and blow the drivers. Then you need to replace the PCM.

This was for 2004-06, but it might apply to yours if it's a 3.0L.
buy at tascafordparts.com.

Misfire DTC codes identify which cylinder is misfiring.

Misfire Detection Monitor The Misfire Detection Monitor is an on-board strategy designed to monitor engine misfire and identify the specific cylinder in which the misfire has occurred. Misfire is defined as lack of combustion in a cylinder due to absence of spark, poor fuel metering, poor compression, or any other cause. The Misfire Detection Monitor will be enabled only when certain base engine conditions are first satisfied. Input from the ECT or CHT, MAF and CKP sensors is required to enable the monitor. The Misfire Detection Monitor is also performed during on demand self-test.

1. The PCM synchronized ignition spark is based on information received from the CKP sensor. The CKP signal generated is also the main input used in determining cylinder misfire.

1. The input signal generated by the CKP sensor is derived by sensing the passage of teeth from the crankshaft position wheel mounted on the end of the crankshaft.

1. The input signal to the PCM is then used to calculate the time between CKP edges and also crankshaft rotational velocity and acceleration. By comparing the accelerations of each cylinder event, the power loss of each cylinder is determined. When the power loss of a particular cylinder is sufficiently less than a calibrated value and other criteria is met, then the suspect cylinder is determined to have misfired.

1. Misfire type A:
   
   Upon detection of a Misfire type A (200 revolutions) which would cause catalyst damage, the MIL will blink once per second during the actual misfire, and a DTC will be stored.
   
   Misfire type B:
   
   Upon detection of a Misfire type B (1000 revolutions) which will exceed the emissions threshold or cause a vehicle to fail an inspection and maintenance tailpipe emissions test, the MIL will illuminate and a DTC will be stored.
   
   The DTC associated with multiple cylinder misfire for a Type A or Type B misfire is DTC P0300.
   
   The DTCs associated with an individual cylinder misfire for a Type A or Type B misfire are DTCs P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0309 and P0310.