Rough Idle

Here is my 78' F250 with a 400 engine. When started it stumbles badly for about 5 minutes. After that the vacuum comes into the normal range and it runs smoother.

Category:

Education

Tags:

• Idle

[badderthanyou]

@TheFordlover2010 Does it look like a vacuum leak? Bad valve? Carb problem?

[TheFordlover2010]

@gilberto1533 umm bud this is a carbarated 400 big block so no maf, injectors,air filter,and fuel filter would do that to it either it would be choking or starving for gas causing it to gag. and no icv either

[zloben9000]

Looks like a Vacuum leak.

you have to blow cigarette smoke to find it.

When cold of course !

worming it up seals the leak.

I would say intake manifold O RINGS at the engine ..

The intake has Rubber rings on the engine it could be that.

Blow smoke first !

[gilberto1533]

I had that problem in my Explorer Sport 2002...

I solved doing the following..

1) -- Clean the MAF

2) -- Clean the Throttle Body

3) -- Clean the ICV

4) -- I replaced the fuel filter

5) -- I replaced the Air Filter (I use K&n)

6) -- Finally use a inyector cleaner (I use Lucas)

Good Luck... you will see that will solve the rough idle