[olddog]

I have a miss that I can not find at all and it is usually only in first or second gear. My fuel cut off is 6800 and I usually shift at 6200 and just as I am putting in the clutch, or about to I get a dead miss.

Hmm, classically high speed misses are either leanness or spark. Put in plugs (NGK) one step colder and it got a touch better. Noticed a burn mark on one of the metallic boots and replaced the wires with Magnecores and it is better yet but still misses some. Damn!!

I suppose the next move is to do a voltmeter check of the injectors but you would think a bad injector would miss below 6000 rpm.

Any ideas out there as I am just scratching my head.

I am considering going back to the normal plug and jut closing the gap to about .032 to see if that does anything - - which I doubt.

Always willing to hear suggestions or ideas.

This is a PITA!! :down:

 

[iburke]

your fuel cut off is not failing and kicking in early is it. Sounds like a loss in fuel pressure...:huh:

 

[olddog]

It could be but I will need to go to the damn dealer for that and this will cause all kinds of $hit about who can and can not drive my car . . .

I just don't think it is that but it could be.

 

[iburke]

Will it run on up to the 6800 fuel cut off....or does it just diie back to 6200

 

[olddog]

Hard miss like a plug or a carb lean miss at about 6200 - - out of nowhere.

Will check fuel filter and the impedance on the injectors as the electrical (spark)
seems to have been taken care of - - clueless at this point.

Were it the 522" I would say plug or lean . . just something else to occupy my thoughts for a while . .

 

[lehmannhenry]

could you have a sticking injector? At low RPMs it wouldn't be noticed since it has time to be forced open, but at high RPM that isn't the case. JAT

 

[olddog]

Could be but doubtful as it only does it over 6000 rpm; still, I will check the impedances for them to see if one is out of spec.

 

[olddog]

I 'may' have found the problem.

I was reading the service manual about engine miss and there are about fifty or more things that could do this so I started thinking about it logically and something seemed to ring a bell with me.

One of the reasons for a miss is the MAP or the grommet around the MAP where it goes into the manifold. **I seem to remember something about my grommet being bad** Checked it and it was vrey 'loose' in the intake; as such, I pulled it out and I saw what I think is/was electrical tape but the thing was sure loose in the intake.

Anyway, I wrapped it with fresh electrical tape for a snug fit and put it back into the intake manifold. Hopefully I will get it out tomorrow and see if this fixes the miss OR if it manifest any new problems.

If it fixes the miss I will simply get a new MAP sensor with the grommet.

Here's hoping that was what it was . . . :thumbsup:

 

[olddog]

Problem is fixed!

It was the gasket, or lack of one, on the MAP. Wrapped it with electrical tape and made it tight and problem is gone: just ordered a new MAP with an extra seal . . . Seems that the car will go lean at high RPMS if this is the case.

If it comes back I will have to eat the above.

 

[Mark06C6]

love it when a plan comes together, glad to hear it was not something serious:thumbsup:

 

[olddog]

I am just glad I found it and I am glad I changed the junk plug wires too . .

 

[olddog]

CURED !!

It was the MAP sensor, seems the unit lost it's red grommet. Got a new sensor and an spare grommet and all is well.