Cadillac Deville

Cadillac 1987 125,000 4.1L 250ci v8
my question is I just got new exhaust sys. And the mechanic said there is something wrong because during intial start up the exhaust temp with so high it was making the new pipes turn blue and was making the cat. Glow red- also the engine has been idling very high and would make the engine surge in stop and go driving? We shut off and couple mins. Later and it was fine.

Is there something wrong with egr or the idle please help?
October 2, 2007.

Have the coolant temperature sensor and idle air control valve check.

Oct 2, 2007.
How rough is it Idling? Has this been checked?

Oct 5, 2007.
Inbox : Message
From: cadillacp2003
To: rasmataz
Posted: Mon Oct 08, 2007 6: 56 am
Subject: Re: RE: exhaust temp and idle problems
okay I replaced the egr valve and that stopped the high exhaust temp but it stlll surges especially when you give it gas to get over 30mph-it sounds like it is stalling then you get off the gas it returns to normal- is IACV the problem. Also I was told it needs a tune up and the timing is off will that make it surge

IACV will not do that-tune -up might worked, might want to scan the computer's live data on the TP/Load/Coolant/O2 sensors-could be also a low fuel pressure problem-injectors clogging and pressure regulator not maintaining the pressure.

Oct 8, 2007.