What is considered a normal idle

CaptainXL

Member
Dec 4, 2011
2,445
Sparky said:
Blowby would cause pressurization of the crankcase, not the valve covers.

Lol. The valve cover is connected to the crank case. How else does the oil drain back to the pan? What I said is valid. He needs to do a compression test. Low compression can cause misfires.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
ok so no compression test done yet.... i know im getting to it been too busy.

So all previous tests were done while car was at operating tempurature but just around the town kind of driving.

So a couple times i had to drive a little further about 15 miles to and 15 back and it seems that the hotter everything gets the better it acts.

after the first 15 miles i shut truck off and before this idle was extremely rough i can hear my battery box rattling around annoying as He**

so i shut truck off go do what i hadda do prolly 15 minutes go start her back up and she's purring like a kitten smooth idle no rattling so i put it in gear and obviously theres a load on now so a slight vibration but nothing major and she drove all the way back with a couple stops at a store smooth as can be.

question is i know like with my exhaust manifold when it was cracked that it was louder at cold start and heated up would be quiet again.

What would heat change that would cause the engine to run poorly and misfire?


just an idea i had that could get to the cause of my issue..

Will try for a compression test this weekend but no promises (my gf's bday)

Thanks again for all your help
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
jeffro312 said:
What would heat change that would cause the engine to run poorly and misfire?
Coil packs. Wiring harness with a flaky break. Intake manifold gap that creates a vacuum leak.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
the roadie said:
Coil packs. Wiring harness with a flaky break. Intake manifold gap that creates a vacuum leak.

Thanks roadie I think you understood my question but now that I read it I meant

what would heat change to cause rough idle and misfires to go away. As when its hot and running problems disappear
 

CaptainXL

Member
Dec 4, 2011
2,445
Have you removed and cleaned both sides of the throttle body? Once that's done check vacuum. Should be about 18 in hg.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
CaptainXL said:
Have you removed and cleaned both sides of the throttle body? Once that's done check vacuum. Should be about 18 in hg.

Yes to the throttle body cleaning I'd lick it its so clean....

I'll check vacuum this weekend if I can get away from the gf.


I have this hunch though is it possible a leaking exhaust manifold to cause any of this...... just a slim chance but before I bought car they replaced exhaust manifold and snapped a bolt in block never fixed it so there's just no bolt there rest are toqued to spec I'm possible airs getting in there and fucking with 02 sensor.. think I mentioned this before but not sure
 

CaptainXL

Member
Dec 4, 2011
2,445
jeffro312 said:
Yes to the throttle body cleaning I'd lick it its so clean....

I'll check vacuum this weekend if I can get away from the gf.


I have this hunch though is it possible a leaking exhaust manifold to cause any of this...... just a slim chance but before I bought car they replaced exhaust manifold and snapped a bolt in block never fixed it so there's just no bolt there rest are toqued to spec I'm possible airs getting in there and fucking with 02 sensor.. think I mentioned this before but not sure


The 02 sensor isn't the cause because it doesn't come into play until the engine is hot. Its more than likely correctly subtracting fuel when in closed loop. Which will smooth out the idle. So your more than likely too rich. Check for leaking FPR.
 

jeffro312

Original poster
Member
Oct 4, 2012
442
East Haven,Ct
Can u guys listen to this video clip closely. After I rev when rpm settles listen to the odd noise.

This is I think the vibration

Also there's that loud tick that comes and if I restart truck goes away

Also if I drive over 20 miles after truck reaches operating temps the vibration lessens. Vibrates more in a gear but still a lot in neutral or park. Seems louder when I turn the wheel at a stop

[video=youtube;KkhQjnI9PUc]https://www.youtube.com/watch?v=KkhQjnI9PUc&feature=youtube_gdata_player[/video]
 

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