Brukh

Just replaced a cracked exhaust manifold on an 88 Topaz. Now it won't idle, gets bad gas mileage, runs rough, and black soot is coming out of exhaust. Fuel pressure varies from 50 to 55 lbs. Had a MAP sensor code and replaced with a used one. Also replaced MAP hose. Didn't help. Any ideas? Also, shouldn't codes clear when battery is disconnected?

360ci

If the code wasn't fixed, reconnecting the battery won't get rid of the code. Only when you fix the problem and reflash the system will the code stay away. I suggest a Tune up with new plugs & wires. A compression check on all the cylinders. Black soot generally means your burning oil, so worst case would be you have a piston ring worn. To cure the idle - replace the TPS and/or IAC sensors.

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'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!

tbird100636

Blue smoke means oil burning. Black soot indicates an overly rich mixture, which would be the result of a bad MAP sensor, which Brukh said he has. Never replace a MAP sensor with a used one. Read this thread that I replied to a while back. It details how to test the MAP sensor.

86 Tempo- rough idle, poor mileage, soot in exhaust

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Master ASE Certified L1 Chrysler Technician- still a Ford fan at heart.
1964 Thunderbird Hardtop- Chantily Beige- 390 FE 4V V8-Uncle's Car
1966 Thunderbird Convertible- Red- 390 FE 4V V8- Uncle's other car- waiting for paint and body work!!!
1967 Mustang Convertible- Blue- 289 V8- helping a friend re-assemble this classic