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91 Eldorado 4.9 / Rough Idle

2201 Views 3 Replies 2 Participants Last post by  Ranger
I have a "91" Eldorado 4.9 with 138,000 miles that is idling rough, and also has a consistent miss. The engine rpm's are also rather high at start-up before quickly setttling down. I have put on a new EGR valve, Cleaned the throttle body, Put on a new distributor & Wires, New air filter. In spite of this, the rough idle and miss continue. The plugs were recently changed about 9 months ago, so I don't suspect a problem there. Could my problem perhaps be vacuum related? Any help would be greatly appreciated!

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When you cleaned the TB did you rod out the EGR tubes in there?
If you are refering to the 2 tubes located right under the throttle body, yes I did. One of them was about 75% clogged with carbon. I cleaned it out with carburetor cleaner and a hanger. It made a noticeable improvement, however the rough idle still persists. To be more specific the idle is relatively erratic. It will run the gambit from running relatively normal, to running very rough, to sounding as if it's gasping for air periodically! I am still stumped. Do you have any other suggestions?

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