[johnT_5789]

Recently I removed the upper intake manifold to clean the clogged EGR passageway. After re-assembling, it ran perfectly for about 30 miles, with more power, quicker acceleration than before. About 30 miles after putting it all back together it started to idle rough, and run rough under load and when accelerating. It also now takes a lot more accelerator to keep it up to speed when cruising. Has anybody had a similar experience , or found a solution? Thank you!

 

[oldskewel]

Recently I removed the upper intake manifold to clean the clogged EGR passageway. After re-assembling, it ran perfectly for about 30 miles, with more power, quicker acceleration than before. About 30 miles after putting it all back together it started to idle rough, and run rough under load and when accelerating. It also now takes a lot more accelerator to keep it up to speed when cruising. Has anybody had a similar experience , or found a solution? Thank you!

I had similar symptoms once and they turned out to be partially caused by a leaking intake manifold gasket. I'd recommend you remove the manifold again, clean the gasket and surfaces carefully, and reinstall and torque carefully. Maybe even replace the gasket if it looks bent.

 

[G8ROdy]

Did you tighten the manifold bolts and nuts in the correct order and to the correct toque? I would also check the hoses and electrical connections. Did any intake cleaner get into the MAP sensor? Basically recheck everything. Sorry if you have done all of this, I'm just trying to help.

 

[mjody]

Sounds like you put the black upper plenum gasket on backwards. There is a "tab" that should be visible on the firewall side of the d/s upper end of the plenum. If you put it on backwards, the EGR dumps to the wrong passages and causes your issue.
To correct, pull that small metal plate covering the top of the plenum. Make sure the "tab" is at the 2 O'Clock position and re-install the cover.

 

[G8ROdy]

johnT_5789 did you solve this?