Moose rough start

[LeoC2]

This is weird, was having a bad idle so I put in a new Motorcraft IACV. Now Moose has a very rough start when cold, shakes and shudders badly then smooths out within 15 seconds or so. The valve did not have a gasket included but parts store is getting one for me on Monday.

Any ideas?

 

[driller]

These things usually end up being vacuum leaks and it appears the lack of the IACV gasket exacerbated the problem. But it sounds like a cold idle throttle problem, so you can't rule out ignition or fuel either.

Cleaning the MAF sensor is an easy go-to fix as well.

If you haven't already, check for codes.

 

[billcu]

Also, did you disconnect the battery after replacing the IACV?

 

[LeoC2]

Also, did you disconnect the battery after replacing the IACV?

No, should I have?

- - - Updated - - -

These things usually end up being vacuum leaks and it appears the lack of the IACV gasket exacerbated the problem. But it sounds like a cold idle throttle problem, so you can't rule out ignition or fuel either.

Cleaning the MAF sensor is an easy go-to fix as well.

If you haven't already, check for codes.

It's pouring rain today (better than snow!) but tomorrow I'll clean the MAF, install the gasket, it's also time I should replace all the coils and plugs, been a while since I did that.

 

[billcu]

Yes, disconnecting and reconnecting the battery will let the computer readjust the idle.