Solved Cold AM Miss Code 300...306 RESOLVED
#1
![Default](/forum/images/icons/icon1.gif)
For over a year my X Type suffered from a cold morning miss, blinking check engine lights and poor performance until the car warmed up. It is not a problem in the summer but with the onset of cooler autumn weather here in Minnesota it came back again.
This time I changed the LOWER INTAKE MANIFOLD gaskets and the the problem is solved. Previously, I changed the upper gaskets and it improved a little I suffered all last winter with no fast idle, misfires and crappy performance until the car warmed up. After it warmed up in the morning it was good for the rest of the day but every morning it was the same old stuff.
You can change the lower without removing the injectors. You can turn the lower manifold sideways and easily change the six lower gaskets. Be careful not to dump sand or dirt down the intake ports. I covered mine with tape while I worked. I also applied a little extra sealant-not necessary but could be helpful.
Be careful to note the order of the three different lengths of manifold bolts or you are going to have quite a puzzle putting it back together. Trust me, I learned the hard way. Also if you have not changed your plugs in a while it is a great time to do it. You might also consider doing your valve cover gaskets.
Tip, if your two vacume lines that go into the manifold break when you try to remove them. Just stick them back in and slather the holes with gasket sealer. it works fine and lasts,
If you can get a large diameter shrink tube you can shrink a segment around the one way valve in power brake booster line and also that hose that always fails between the valve cover and the intake. Just a cut segment as long as the hose and apply heat and good as new and save yourself 50 bucks.
This time I changed the LOWER INTAKE MANIFOLD gaskets and the the problem is solved. Previously, I changed the upper gaskets and it improved a little I suffered all last winter with no fast idle, misfires and crappy performance until the car warmed up. After it warmed up in the morning it was good for the rest of the day but every morning it was the same old stuff.
You can change the lower without removing the injectors. You can turn the lower manifold sideways and easily change the six lower gaskets. Be careful not to dump sand or dirt down the intake ports. I covered mine with tape while I worked. I also applied a little extra sealant-not necessary but could be helpful.
Be careful to note the order of the three different lengths of manifold bolts or you are going to have quite a puzzle putting it back together. Trust me, I learned the hard way. Also if you have not changed your plugs in a while it is a great time to do it. You might also consider doing your valve cover gaskets.
Tip, if your two vacume lines that go into the manifold break when you try to remove them. Just stick them back in and slather the holes with gasket sealer. it works fine and lasts,
If you can get a large diameter shrink tube you can shrink a segment around the one way valve in power brake booster line and also that hose that always fails between the valve cover and the intake. Just a cut segment as long as the hose and apply heat and good as new and save yourself 50 bucks.
The following users liked this post:
JimC64 (10-15-2014)
#2
Thread
Thread Starter
Forum
Replies
Last Post
Guy-Pierre Boucher
XJ XJ6 / XJ8 / XJR ( X350 & X358 )
7
09-16-2015 05:55 PM
OkieTim
S-Type / S type R Supercharged V8 ( X200 )
3
09-08-2015 04:48 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)