Engine Feels like miss firing......?

essgt1

New Member
May 20, 2011
19
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2
Florida
Hi all,
Here is the problem. Lately when I first start my mustang and drive it feels like it is miss firing (breaking up or as if the mufflers are clogged) for the first 5 to 10 minutes or til she gets warmed up. After she is warmed up she runs strong as if it never happened. There are no cats on the car and has a BBK h-pipe with shorty headers. Was wondering what the issue may be and if it is a simple fix. All your suggestions are muchly appreciated.
 
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Unfortunately no , I dont have one of those code readers. Did it again today, almost sounds as if it wants to back fire but doesnt.

You don't need a code reader. All you need is a paper clip or a piece of wire and maybe a test light if your mustang doesn't have a CEL. Search the tech sticky for Jrichker's post about how to pull codes. It is very easy and should be your starting point as the computer will often tell you provide you with the codes where the issues are.
 
Sounds like you have a collapsing lifter or a compression problem on startup. Here's what I'd do: Turn the ignition on. Floor the gas pedal and hold it, which invokes "clear flood" mode and actually shuts off the fuel. Crank the engine for a few seconds and listen to it. Does it go r-r-r-r-r-r-r-r all nice and even, or does it go R-r-r-r-R-r-r-r getting louder as the crank passes a weak cylinder? Poor man's quicky compression test. It won't tell you which cylinder is weak unless you pull the distributor cap and watch where the rotor is pointing as it passes the weak cylinder, but it'll definitely tell you if you have a weak cylinder. And a weak cylinder is only caused by valves not actuating properly or the cylinder not sealing properly.

So, if it clears that quick and easy test, you can rule out compression and move on to spark and fuel.
 
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Sounds like you have a collapsing lifter or a compression problem on startup. Here's what I'd do: Turn the ignition on. Floor the gas pedal and hold it, which invokes "clear flood" mode and actually shuts off the fuel. Crank the engine for a few seconds and listen to it. Does it go r-r-r-r-r-r-r-r all nice and even, or does it go R-r-r-r-R-r-r-r getting louder as the crank passes a weak cylinder? Poor man's quicky compression test. It won't tell you which cylinder is weak unless you pull the distributor cap and watch where the rotor is pointing as it passes the weak cylinder, but it'll definitely tell you if you have a weak cylinder. And a weak cylinder is only caused by valves not actuating properly or the cylinder not sealing properly.

So, if it clears that quick and easy test, you can rule out compression and move on to spark and fuel.
Thanks , will try ou and let you know what i find
 
Thanks , will try ou and let you know what i find
Ok MFE92, I tried what you said and it definately sounds like R-r-r-r-R-r-r-R. If a cylinder doesnt seal properly would you burn more oil or a least smoke coming out of the tail pipe on the side in question? My oil levels are fine and still has that honey color to it. How bad can this issue be?