99 blazer - runs rough/chugs when cold
 

Hello all! This is my first post... I've searched through many of the topics and already found the materials useful. But, I can't find a specific solution to my problem, or, more accurately, I'm not totally sure how to figure out what to fix...

I have a 99 2 door s10 blazer, 4x4. Symptom is rough running, poor power, general "chugging" when accelerator is pressed, but only in the morning, until it has driven 5-10 miles. After that, even if it sits for 8-9 hours at work, it starts up great and runs fine - no power or chugging issues. Come home, let it sit overnight, and it will sometimes do it -- seems to definitely do it if it sits for 2 or more days.

I've read some on here and troubleshooted a bit -- checked MAF sensor: looks shiny and new, sprayed some cleaner on it anyways. New air filter, oil just changed. Pulled EGR valve, cleaned it out, put new gasket with screen in. Run one fuel tx through (but kinda cheap one). Was going to change the fuel filter, but had problems with the bracket -- plan to change fuel filter this weekend.

My current thought is this could be bad gas, as I haven't run a full tank through yet and it's odd how only in the morning, if it sits for a while -- maybe water separating over night and burning through? I've bought a bottle of Seafoam, to use part in the gas tank with a fill up. I'm thinking I'll check the Throttle Body and clean it up. I don't think O2 because it goes away when hot, not get worse when hot, right? What about Coolant Temp Sensor? Would this do this?

It does have an engine light up, but this has been up for a year or so -- was told it was an EVAP code linked to the EVAP canister and that it didn't need to necessarily be replaced yet, just might affect MPG a bit. It has not been a problem the whole time.

Any other thoughts/ideas/questions? Please help -- love to fix this and not spend a ton of money paying a mechanic to guess as well.

advance auto or other part stores will scan your computer for free..get the code and we can go from there

HELP!!..........MORNING MISS.......Driving me nuts!!
 

HELP!!..........MORNING MISS.......Driving me nuts!!
99' Blazer 4X4 full size 4.3
Has anyone figured out the problem with the MORNING MISS?:icon_shrug:
I've had it in the shop for a total tune up, fuel pump pressure test, changed the distributor out and it's still there. Just in the morning till the engine warms a little, than it will run like new for the rest of the day; no matter how long it sits you can't get it to miss???

PS. The Morning miss only happens when I take off at normal speeds. If I take off like a dragster, with the peddle to the metal, it does not miss. Go figure!!
Morning miss started @ about 125000 miles.

a weak lifter will cause a misfire too..just a thought