My car start to chug sometime ago and hasnt gotten any better and seems to get a little worse.
It chugs when I am going around 20-30 in drive and 40-45 in overdrive, the rpms are usually under 1000rpms when this happens. After running a fuel system cleaner through it it seems to clear up the problem but then after a while it starts chugging again. And the other night I shut it off and went to start it back up in less than a minute and it wouldnt start it just turned over until i stepped on the gas a little, but this has happened only once. Im guessing many things could be leading to this problem but if anyone has an idea i would like to know. Ill be storing it for the winter in a few days and will take it to a shop to get a tune up and have them check everything over.

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1989 Trans am 305 TPI Automatic, 2.73 rear, K&N filter, underdrive pulleys, air foil, tb bypass, low restriction exhaust

 

Bonz,

I'm not sure if your "chug" is the same as the "surging" I had, but...

My 89 Formula 350 TPI would surge forward then idle down (especially at low RPM's). I too had the fuel cleaner run through my system with minimal/temporary results. In the end, it turned out to be a carboned-up Idle Air Control (IAC) sensor and 5 out of 8 of my fuel injectors were out of spec.

*I would check the IAC first. If it needs cleaned/replaced, I would do so.

If this doesn't fix your problem, I would check the injectors with an ohm meter. Each injector should have between 11 and 14 ohms of resistence (according to my Haynes manual).

Hope this helps.

 

It defenetly isnt surging. Ill have to check that stuff out this winter. THAKNS

 

you description sounds like a clogged fuel filter

 

Even running good you can't expect too much from a 305 Auto in OD trying to accellerate from under 1000 rpm.

 

the drivetrain in the 305 tpi auto cars had a torque converter that locked up at around 25 mph if i remember correctly. you could probably do something by changing the shift points or just stomping on it and getting up to speed...but the chugging i think youre talking about is what our cars will sound like if the converter is locked up at extremely low rpms, and theres not nearly as much power down there so it will seem like it takes forever to accelerate and is just chugging...but if you push it to the floor...well thats another story, it should upshift and the converter will come out of lockup. im assuming it doesnt chug when you do this? . if not you could have an exhaust leak..

 

Due to the year of your car and your description of turning it off then failing to restart sounds like your fuel injectors are leaking down.

Comparable to a car flooding on a carbed model.

I took all my injectors plus the cold start valve and sent them to Rich at Cruzin Performance.

http://www.cruzinperformance.com/

Whereas he rebuilt them and flow matched them to within 2% of each other. When he got my injectors all 8 were leaking down and had a 33% difference in flow rate.

The difference was night and day...... just a thought.