Problems when it gets warmed up.

[chrisorbics]

Hi, I've been having a lot of trouble with my 1999 maxima lately. When it's cold it runs good unless you let it sit in one spot and warm up for awhile. then it will run real shakey till it cools off. Today it was hot out and it running really bad. So i'm guessing when it's warmer outside the engine get's hotter and that is causing the problem. I'm thinking engine coolant temperature sensor but I haven't checked it yet. I just checked the IAT sensor with a multimeter and it seems ok. I'll probably do the same with the coolant temp sensor tomorrow. I thought I had bad coil packs so I changed three of those the other day. But that wasn't it. If anybody needs the rear hanshin packs i have three extra's. So am I thinking corectly? Any help would be great.

Thanks, Chris

[maxhopper]

Welcome to NICO.

I wouldn't think that a coolant temp sensor would cause the problem you are describing. Things you should check for are: vacuum leaks, malfunctioning EGR system, bad cylinder compression, and leaking head gaskets.