97 2.7l misfire/smoke on startup

Hey guys so i have a 1997 Tacoma 2.7l and I just recently bought it. It has a problem that no one can find. Had it for about 6 months and after 4 months it started to have a slight rough idle at a cold start up, then it continued to get worse. Now at startup it has a misfire for about 1-5 seconds and it steams out of the exhaust pipe for about 30-40 seconds. Its quite a hefty amount of smoke too. I've watched the coolant level and I'm very very slowly loosing coolant. There is no oil in the coolant and the oil has no coolant in it. It has one code which is P0420 (bad catalytic converter). My whole family knows a good amount about cars and trucks and no one can figure it out. I did a block test which tested negative for any traces of hydrocarbons in of the radiator. I also did a compression test and it had 175, 175, 170, 175. So I brought it to the dealership. They had it for a week and they only had it misfire twice and it never smoked on them. They said they "sniffed" it and it had high hydrocarbon at startup (over 1000) but then it leveled out. It has never over heated. It sounds like a head gasket or cracked head to me, but the engine is a brand new engine with only about 40k miles on it. Any ideas on what this could be?

 

bump

 

I second the head gasket

 

I've told this story all over this site, but just in case you haven't read it somewhere else. My 3RZ 2.7L had a cracked head and the same symptoms yours has. It actually had four cracks in it. Mine was getting slightly hotter but never overheating and it was losing coolant. You could also hear bubbles in the heater core. You may not have that, but I did and it was a great indicator other than the startup misfires that something was wrong. I ended up having a shop buy a new head casting and swapping over all of the parts (valves and such) while putting in new valve stem seals and other non reusable parts. Cost about $2350 all said and done with new OEM headgasket and rebuilt top end, it's like a new motor now. It was running okay otherwise but I had all this done about 10,000 miles ago at 190K.

 

Just to let all you guys know I brought my truck to a buddy who had a sniffer and it read 1608 hydrocarbon levels warmed up coming through the radiator. HEAD GASKET IS BLOWN. May still be cracked heads... Going to start pulling it apart here this weekend. Gonna tackle this one myself. After dropping an engine in a f150 that was to high for the cherry picker to reach, I think I should be able to do a head gasket/rebuild. Should I post a thread of the job? It may take a while since I am also a college student with a job who's broke

 

Hey everyone the head gasket replacement thread is done! Go check it out!!

https://www.tacomaworld.com/threads/replacing-97-2-7l-tacoma-head-gasket.432103/