1988 Chrysler Fifth Ave - skip/hesitation

This problem really has me stumped! I will explain the problems first:

1. Rough idle when cold. Engine seems to be running on six cylinders instead of eight. No problem when engine is fully warmed up.

2. Engine skips, hesitates, and bogs down while cruising between 35 and 45 mph. This problem does not occur while under acceleration.

During the past two months I did a complete tuneup to include a new carb, timing chain, oxygen sensor, and new CAT. I am really stuck. This car is mint and I want to keep it. Any help will be greatly appreciated. Thanks.

what carby r u running? did it have the problem before the tune? did u do the work your self? could be a vaccume leak maby, or carby size what cubic inch is the engine? is it stock? i can maby help more if u answer these questions.

Engine is stock - 318 V8 with a 2 barrel carb. All vacuum hoses replaced. Had same problem before tuneup. Work was done at a local garage using diagnostic test equipment. Thanks.

All vacuum hoses replaced.
What i ment by vaccume leak is from carby to manifold or from manifold to head. could also be a crack in manifold but if they used diagnostic equipment that should have come up. but still, there is a chance that might be it. other than that nothing comes to mind but i will think about it and also might ask a mate who is more experienced (been a mechanic for 30yrs) and see what he thinks.

Problem has been solved! In 1988 Chrysler had the Lean Burn System. This consisted of a Spark Control Unit which in my case was attached to the air cleaner housing. Since all other components were changed there was nothing else to replace. Once the unit was changed my car felt like it was brand new. What a huge difference! Thanks for the help. This thread can now be closed.

http://files.automotiveforums.com/gallery/watermark.php?file=/503/342270lean1.jpg

Problem has been solved! In 1988 Chrysler had the Lean Burn System. This consisted of a Spark Control Unit which in my case was attached to the air cleaner housing. Since all other components were changed there was nothing else to replace. Once the unit was changed my car felt like it was brand new. What a huge difference! Thanks for the help. This thread can now be closed.

http://files.automotiveforums.com/gallery/watermark.php?file=/503/342270lean1.jpg
*laugh*

I was just about to suggest that. My '78 Chrysler Cordoba's Lean Burn computer was defective when I bought it. Instead of putting a new Lean Burn in I switched back to the early seventies Electronic, which required a vacuum-advance distributor as well as some harness modifications, but it was all definitely worth it.