Missing when engine cold

[laxman21]

Title says it all. Misses while giving light to moderate throttle when engine is cold. Once you drive a few miles, miss disappears. Misses were in all cylinders and more were in the 1,3,5 side.

Does it in the AM , but not in the PM drive home from work.

[MT-2500]

Originally Posted by laxman21

Title says it all. Misses while giving light to moderate throttle when engine is cold. Once you drive a few miles, miss disappears. Misses were in all cylinders and more were in the 1,3,5 side.

Does it in the AM , but not in the PM drive home from work.

Your blazer?
Any codes?
How is the fuel pressure?
Plugs and wires and cap?
Camshaft retard setting?

[laxman21]

Originally Posted by MT-2500

Your blazer?
Any codes?
How is the fuel pressure?
Plugs and wires and cap?
Camshaft retard setting?

MY blazer

no codes

Replaced plugs on mechanics suggestion.

I am thinking that I am getting moisture in the cap.

[MT-2500]

Originally Posted by laxman21

MY blazer

no codes

Replaced plugs on mechanics suggestion.

I am thinking that I am getting moisture in the cap.

If it is missing there should be codes and a flashing engine light when misfiring.
Could be moisture or cracked cap.
Always replace cap and rotor with AC delco cap and rotor.
Also camshaft retard setting of will cause misfire.

Miss on just one side could also be vacuum leak or intake leak.
Is this the one you had a brake booster problem on?
If so make sure no vacuum leakes there.

[534BC]

check manifolding and cap to see what is common on that side.

[laxman21]

Took the cap off last night and cleaned the terminals.

Got a code this morning for cylinder 4 misfire.

[laxman21]

Originally Posted by MT-2500

Always replace cap and rotor with AC delco cap and rotor.

What about delphi? Aren't they the same?

[MT-2500]

Originally Posted by laxman21

What about delphi? Aren't they the same?

Not sure delphi makes caps and rotors.

[laxman21]

Originally Posted by MT-2500

Not sure delphi makes caps and rotors.

THey do according to rock auto

DELPHI Part # DC20009
http://www.rockauto.com/catalog/moreinfo.php?pk=1323296

[MT-2500]

Originally Posted by laxman21

THey do according to rock auto

DELPHI Part # DC20009
http://www.rockauto.com/catalog/moreinfo.php?pk=1323296

Well that proves that Delphi does make a dist cap for GM.
They make quite a few OEM electrical parts for OEM GM.
Computers and fuel pumps and other stuff.

Where are you at on the miss now?
Just no 4 or still 1-2-3 cylinders?
Go over the basics first.
Cap and rotor and wires and plugs and fuel pressure and vacuum.
Have you checked the egr valve?
What is engine vacuum reading at idle and at 2K RPM?
What is camshaft retard reading?

[laxman21]

Originally Posted by MT-2500

Well that proves that Delphi does make a dist cap for GM.
They make quite a few OEM electrical parts for OEM GM.
Computers and fuel pumps and other stuff.

Where are you at on the miss now?
Just no 4 or still 1-2-3 cylinders?
Go over the basics first.
Cap and rotor and wires and plugs and fuel pressure and vacuum.
Have you checked the egr valve?
What is engine vacuum reading at idle and at 2K RPM?
What is camshaft retard reading?

Was no 4 yesterday.

Took cap back off and used wire drier and some dielectric grease like old master recommended in another thread.

Ran better and no codes today, but still seemed to hesitate or miss at low rpm and slight throttle.

Looked like the rotor electrode was worn down some, when compared to a new one.

I am going to order a GM one and take the aftermarket back.

[MT-2500]

Originally Posted by laxman21

Was no 4 yesterday.

Took cap back off and used wire drier and some dielectric grease like old master recommended in another thread.

Ran better and no codes today, but still seemed to hesitate or miss at low rpm and slight throttle.

Looked like the rotor electrode was worn down some, when compared to a new one.

I am going to order a GM one and take the aftermarket back.

Also check camshaft retard setting.
If it is off the cap terminals and rotor will burn and sometimes a new cap will change setting.
Also cause misfire.

[laxman21]

Originally Posted by MT-2500

Also check camshaft retard setting.
If it is off the cap terminals and rotor will burn and sometimes a new cap will change setting.
Also cause misfire.

Also check camshaft retard setting.


OK....How?

[MT-2500]

Originally Posted by laxman21

Also check camshaft retard setting.


OK....How?

First step is to get it on a engine capable scanner.
Plain OBD11 scanners and code readers will not do the job.

Get camshaft retard reading from a engine capable canner and if over -1-2 or +1or2 degrees off.

You will need to turn dist untill it come back as close to 1-2 degrees or ) degrees as you can get it.

[laxman21]

Replace cap and rotor...back to normal