How can i diagnose why my car seems to run on 6 or 7 cylinders when it's cold?It starts up fine,it just misses really bad on accel for about the 1st 1/4 mile.

 

This is typically because the fuel mixture is too lean and will not ignite when it is really cold. Try riching up your idle mixture 1/2 turn or so and check it. You may try to richen up your choke mixture as well diring the winter. I had the same problem because of my open air cleaner (no reheater hose) and this worked for me. I don't know what type of carb it is so let us know.

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1983 Camaro Z28
Goodwrench 350ci V8, Edelbrock TES Headers, Flowmaster Catback, MSD 6al and Blaster 2 coil, Edelbrock Performer intake, Edelbrock Performer 600cfm carb. T5, 373 rear, Eibach springs, Cervin Vega speakers, Rock. Fos. Sub, Pioneer CD,
email-chris4421@hotmail.com
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"I used to be a Mustang Guy! I didn't know the power of the dark side!!"

 

Or it could be just the opposite and be running too rich. I just went through the same problem, i had my choke on very tight during the summer, but once the temp dropped near freezing it was flooding the *** out of my engine for the first few minutes. It would miss like a son of a bitch at idle, and even worse trying to drive it.
The easiest way to prove / disprove this is to manually open the choke after you start the car in the morning and see if it gets better. I'll bet it does. In that case, you need some combination of less choke / more pull-off. Exactly how to set both of those is something i do purely from feel, so i can't tell you exactly what to do.
Too lean will generally just stall out in my experience. Too rich will run, just miss a lot.
...ed

 

It's all stock including 168000 miles,and yes it burns a lot of oil,especially on cold starts....

 

Is there any smoke? If so, what color is it? Black means too rich. Mine billows when not tuned right.

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'82 Firebird, dead stock, 9 bolt disc rear, over 200,000 miles and still going strong, more to come...

 

If you are seeing black smoke and it smell rich check the vacuum pull off... they are famous for going bad... it is the gold thing on pass sd front of the carb if it does not hold vacuum it is bad... seen this a few times... make it run like crap when it is cold...

zroc

 

Mine does the same, runs crappy when it's cold. When it's chilly to warm, it runs great, but when it's cold outside car sputters when I apply partial throttle to accelerate the car. revs fine when there is no load on the engine, like when I put it in neutral and rev it.

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Zepher
'86 Pontiac Trans Am WS6, 5 Speed:
Edelbrock 1406 Carb, Edelbrock Performer RPM 7101 Intake Manifold.
Edelbrock Open Element Air Cleaner: Flowmaster Exhaust, 160* Thermostat,
Grant GT Steering Wheel, MSD HEI Coil, Taylor 8mm Wires, Recaro Seats,
Alpine CD+Changer,Rockford & Soundstream Amps, Premier TS-1040C Subs, Polk Audio highs/mids.

WS6 Trans Am

 

Thanks all,it turned out to be a bad choke pull off,now a couple more adjustments to it,and i'll be back to running as good as it was...Thanks all !!!!

 

Well, could a disconected o2 sensor cause the same situation?

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--Steve S-- 84 Trans Am 305 HO 5 speed, completely stock will soup up when i get some $$$$$$$$$$

 

Not as originally described, because the sensor and engine have to warm up before it goes closed loop and the sensor starts providing feedback.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.73 unlimited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, TBD heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.