95 Aurora rough idle, surging

[ccastle]

rough idle, surging and sputtering when taking off and accelerating on an incline at any speed. Sometimes worse than others, will even backfire in intake. at times smell fuel at cold start. Replaced wires and plugs (AC) FPR, fuel filter, cleaned EGR. Replaced coils one at a time, no change. Car has 150,000 miles. fuel mileage has not been affected. Any Ideas out there?

[lynzoid]

Bad FPR (yes, again, or more likely gasket - it sucks air into fuel stream) OR leaky injector/s.

[Aurora01]

I would check the intake manifold boot. This is the transition between the intake manifold and the throttle body check the bottom side.

[winrock]

egr, a possibility,, does the check engine light come on when its happening ? If so i'd bet on the egr

[ccastle]

I will ckeck the boot, The SES light has only come on once during this, it ran great for that day it was on. Thanks for the help!

[jay800]

I know this may sound unlikely, but I had the same problem for a long time in my low mileage '99 and after trial and error like you I noticed one or more spark plug tracking (black electro-burn mark) running down the ceramic spark plug - like the spark would jump around the ceramic rather than through it. You may say that the root cause is something else; problem with some other ignition part. Garage thought it was fuel injector problem - all was good. The code reader showed one or two cylinders misfiring. My SES never came on.
Even after replacing expensive plugs/wires and coil parts more than once with the same problems, I finally bought some cheap Champion copper plugs for the Aurora with the ribs on the ceramic.
Here I am almost 2 years later and haven't had a single hesitation/rough problem since! Back then I could predict when the hesitation would happen - after cruising at constant speed, then give a little gas and it was terrible. Also going up slight incline - even backfire!
The car was always fine for a day or two after replacing plugs or wires, then it always started again - until the copper/ribbed Champion plugs.

Check your platinum plugs for an indication of tracking! Or better yet, put some some cheap copper Champion's in there and give it a shot. Who gives a ratt's ass if 'they say' to use platinum or expensive Delco. Mine is running amazing on these plugs.

Champion part# RS14YC6 (the regular class copper-core plug)
http://www.championsparkplugs.com/mo...56858&pid=8457