Quote:
Originally Posted by Chevy3+3
I hope my info will get you fixed up! I had the exact same problems with my 88' 454 TBI dually I recently purchased. It ran really rough on cold start ups when temps were 30-40 or below. It would stumble and pop and backfire through the exhaust pipes.
I followed everyones suggestions on here and and replaced the coolant temp sensor, tbi base gasket (which was leaking) and checked my EGR and still had the problem just as you are.
I noticed my passenger side exhaust manifold was cracked and I thought that was the problem for sure. So I installed a new passenger side manifold and also replaced both donut gaskets on each manifold-tailpipe connection. The next morning it was cold and it started backfiring again!!! I was so frustrated to say the least just as you are. I could still tell I had a little exhaust leak. It sounded like it was coming from the drivers side. So I unbolted the drivers side exhaust manifold to find the exhaust manifold gasket was shot. This was causing cold air to be drawn into the exhaust stream. It also throws off the O2 sensor reading.
After I replaced that gasket and all my exhaust leaks were fixed The problem no longer existed. The truck runs great now and starts great in cold weather as it should......Well as good as a freezing cold 454 wants to start, lol. She grunts and feel like the starter trying to turnover a chunk of lead, lol.
Anyway....my advice is inspect your exhasut system under the hood. I would almost bet money you have at least blown gasket or two or a cracked manifold. I would almost bet money its on the drivers side as well because I had a huge crack in my passenger side manifold and when I replaced it the problem was still present. The reason for that is because the O2 sensor is located on the drivers side tail pipe above the Y pipe connection.
Hope this helps.
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wow, I had not even thought of that. I am excited to try this fix. Ironically, I was driving the truck the other day and thought "it sounds like i have a small exhaust leak" I could hear a tick under the hood. I never would have linked the two. I'll try it and see if that helps. Much appreciated.