1985 F150 engine idle problem

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Oct 14, 2004 | 09:51 PM

Mel Nash

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1985 F150 engine idle problem

I'm new to this site so bear with me if I'm not in the right spot with this E mail.
I have purchased a 1985 F150 2wheel drive 4.9lt six cyl. with carb. standard 4 speed trans.I have been trying to solve a rough idle problem for about a week now.Here is what I have done so far with the engine.
1.Rebuilt carb.
2.Installed new intake and exhaust gasket.
3.Compression test all 150 psi +
4.Checked all vacc. lines and hoses
5.New spark plugs,wires,coil,dist cap and rotor
6.Checked timing good 10 deg BTC
7.Replaced EGR valve
8.Replaced O2 sensor
9.Replaced fuel filter
10.Blanked off vacc. line to brake power booster checked ok
11.Checked choke stove pipe ok
12.Tried high test gas no change
13.New PCV valve

Is there anything else I can try?
I have also checked the routing of the vacc. lines as per the emmission sticker.That part looks fine but ther are other vacc lines I,m not sure if there are hoocked up correct and the Haynes book I have does not show this.Has anyone out ther have a drawing that might help?

Regards Mel Nash

Oct 15, 2004 | 12:53 AM

locknkey

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From: Right Next to U

leaking carb to manifold gasket is a possiblity, have you check useing carb cleaner to see if engine rises when sprayed around carb manifold gasket?

Oct 15, 2004 | 03:28 AM

srercrcr

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If you'll write out your email address I'll send you a nice diagram of the vacuum lines for an 83 4.9, probably the same, maybe a slight tweak.
I'm suspecting the carb, not all rebuilds are alike.

Oct 15, 2004 | 08:00 PM

Mel Nash

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Joined: Sep 2004

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thanks for the quick responce to my E mail.You can send any diagram of the vacc lines to mel.nash@sympatico .ca Also I have installed a new carb to manifold gasket and there is no leak there

Thanks Mel Nash