What would cause one manifold to be hotter than the other one by 100 degrees,could it be the cat.

 

Prolly not. Unless it's laying on top of the manifold; in which case, if it doesn't hop off and run away, it'll eventually cook off.

More likely, the manifolds are slightly different thickness.

 

An imbalance is fuel delivery will cause one manifold to run hotter than the other, ie: faulty injector(s). One restristed cat on a dual cat car will cause the one side to run higher temp as well.

 

Bad intake gasket on that side which allows in more air and leans the air/fuel mixture which makes that bank run hotter.

 

Well,I'm hoping it's a restriction in the exhaust,the cat has never been changed in 25 yrs.so I'm going with the cat and the timing because it keeps coding the co2,mass air flow.maf burn off,and they all have been replaced they are new.'Thanks guys.

 

What exact codes? Multiple codes could be an electrical issue, also affecting the injectors on one bank.

 

Went to the shop and did a diagnostics test,fuel pressure ok.did a smoke test no leaks so that's ok,electrical ok,the mechanic says the cats ok because both manifolds would be similar because I only have one cat,he's leaning more to the fuel injectors,don't need new ones just get the four stage injector cleaning service.

 

On car injection service is of marginal value. Though it won't hurt to try except for the cost to you. Testing for electrical faults is a little more involved than the tech at your shop may realize. I'm talking about visually inspecting and cleaning several ground points on the vehicle. All of those in the circuits for the sensors that threw codes. Analyzing ECM data to look for signs of incorrect sensor data. Also, scoping injector patterns to look for low voltage or high resistance in a driver circuit. The average tech today doesn't know what alot of this is.

Chances are that it is injectors. I hope that they get it figured out without costing you too much.

 

Yes,the mechanic suggested that I see a fellow that he knows that has more experience with driveability problems.

 

Good, at least he's honest.

 

Yea,he didn't even charge me for the diagnostics,he worked on it well over an hour and really couldn't find anything to fix.I was wondering,could the water pump have anything to do with the manifold being extra hot,I ask because the water pump went bad on my way to have the injectors serviced.

 

Aside from those with phenolic impellers(VW, Audi), water pumps don't stop pumping water. They do leak and their bearings fail but as long as they turn and there is water for them to pump, they pump water. If your cooling system was seriously low on coolant, one side may have heated more quickly that the other, hard to say. Does the engine run okay?