Do i have to warm the engine up to check the compression?

SOURCE: 99 buick Lesabre

hey thanks for bringing me up to speed. ive been working on many other problems but with your great explanation i remember.
we need to check the compression on that cyl. and compare it to the compression on 2 other cylinders your choice.
but before you do this get a can of carb cleaner . and with the car idling spray around the intake manifold in the area of #6 cyl. what we are looking for is a small vacuum leak that would also act like this. with the engine idling and spraying around the intake the engines idle sould not change and if it does when you spray you have an intake leaking.
let me know how it turns out.
later
paul

SOURCE: misfire on #6 and #8 cylinder 1996 Dodge Ram 1500

Check the spark plug wiring . There are several places where the wires cross each other. These wire cross points MUST be at right angles to each other. Or you will have a misfiring problem.

SOURCE: 1997 Nissan Altima Cylinder 1 misfire detected.

This Sounds Like a COIL PACK Problem

Vincent G

• 2363 Answers
• Posted on Dec 19, 2009

SOURCE: MIL indicates cylinder misfire on 1, 3, and 5

Check for

vacuum leaks on intake manifold,

the air tube between the air filter.

intake manifold vacuum hose.

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clean throttle plate with Berryman carburator cleaner

SEE sample picture HERE
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Also remove carbon built up behind the EGR valve and the EGR passage tube.

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Vacuum leak WILL offset the intended 14.7 to 1 air fuel ratio.

More un-metered air (leaks) will lean out the fuel mixture.

Use small amount of Berryman carb clearer at potential air leak area will help you identify trouble spot.

At idle,just spray and listen for the RPM surge.

The in-rush of carb clearer will increase the RPM on the motor.

Record the problem spot(s) and address it later.

===

EGR carbon built up require 2+ hours to clean from start to finish.

You will need a new EGR base gasket before your start.

Locate and remove the EGR valve after the vehicle is cool down.

Carefully record the connector and vacuum line (for older vehicle) location by drawing an easily to follow diagram.

Remove the EGR valve.

Inspect the location of the carbon built-up inside the valve and the EGR passage tube.

SOAK these areas with WD-40 spary.

You will need a small screwdriver,cloth hanger and lot of newspaper and time to get this cleaning done right.

RE-SOAK the carbon and let it sit for over-night will also help.

One the last round,pass a shop vacuum of the EGR valve and the passage pipe.

Install the new EGR gasket and connectors.

Allow the vehicle to warm up outdoor to burn up any remaining WD-40.


Take it for a test drive.


Please rate my answer if it's useful to you.


Cheers,

Mustgo

SOURCE: cylinder number 5 misfire, what

I'm assuming the code that was pulled is P0305. Best case would be a bad spark plug on the number 5 cylinder. Keep in mind, the spark plugs are torque sensitive when installing. These are the possible causes that are stated in a Jeep service manual for your vehicle. Check the basics first......Camshaft,crankshaft,valve timing or vacuum problem,ignition coil output is low,engine internal mechanical problem,secondary ignition pattern is irregular, fuel contamination, Fuel pressure leak down is out of spec, fuel pump ampere out of spec, fuel pump capacity out of spec, fuel pressure is out of spec., engine compression, PVC system restriction, Fuel injector #5 is defective or the connection on the injector itself is loose or corroded, Intake gasket defective. It could also be freeze frame data in the PCM, but this is a very very rare cause.