I have a 1996 Nissan Altima. I had to change my radiator recently because it developed some cracks on the top of the tank and I would have to refill the tank every few days.
When I changed the radiator I also changed the thermostat and the two radiator hoses.
After changing the radiator my car started to misfire or die for a split second and come back when I would accelerate while the engine was still cold. This would happen all the way up to until it was at normal operating temperatures. When the tempature gauge needle is around the middle it stops misfiring during acceleration. The engine also takes a bit longer to warm up now in general.
I think i possibly failed CA smog because of this problem too. Since my car is misfiring possibly because of high chamber temperatures which increase my NOx. I specifically failed because of the NO test. These were my results:
CO2 O2 HC CO NO
14.7 0.1 49 0.23 950 15mph
14.6 0.1 37 0.18 700 25mph
Anyways, what do you think what went wrong after I changed my radiator? Because it did not do this before the change only after. Any tips advice on what to do next?