When I do a cold start (it’s around 25 degrees here in the morning currently) if I do not have my foot on the gas it will run for about 5 seconds and then die. If I start it again, it stays running and does not die a second time. If I keep my foot on the gas slightly it does not die. Once running, it will start misfiring at idle. Not bad enough to stop the car or keep me from driving, but enough to notice it and see the shifter shake erratically if I’m at a light. The misfire seems to get slightly better as rpms go up. It continues to misfire no matter engine temp, although the rpms go up from around 750 at startup to around 1000 at idle when warm. This is fairly consistent. If I drive it when the engine is cold it will big down and feel like I cannot speed up properly for the first few minutes of driving. It also does not want to go over around 4500 rpm, although I haven’t pushed it too hard because I’d like to be careful if there is an issue it might make worse.
Work I have done- new plugs, wires, rotor and distributor cap, new coil, new intake manifold gasket and butterfly valve gasket, new flame trap/hose going to the intake itself, new IAC valve, and new vacuum hose and valve for the brake booster. I have also replaced the blower motor and went over all of the vacuum lines on the interior at that time, as well as the rest of the vacuum system and I am FAIRLY sure there are not vacuum leaks.
I also removed and cleaned the intake system and made sure there was no carbon buildup or other issues.
The previous owner replaced the main fuel pump and filter, as well as the in-tamp pump. I have not taken this one out to check and see if it was installed correctly but I do know it’s new.
I am a bit at a loss since I started by thinking it was definitely a vacuum leak but have gone over things and it all seems to be in order.
I have not done a compression test or a smoke test for vacuum leaks since I do not have the tools currently to do so, but I can if you all think absolutely necessary.
Where should I start for further diagnosis? I would love to be able to drive this car but I don’t want to make anything worse. Any help would be appreciated! Pictures are of
car in question.