'99 Blazer erratic shifting and sputtering
 

So....... I can't find anything that matches my symptoms, so I'm starting a thread. Just point me in the direction I need to go or send me a link if you want.

I have a '99 Blazer 4.3L 4WD. 249.5k miles. Pretty well stock everything.

Blew the head gasket a month ago. Milkshake everywhere. Cleaned everything and assembly lubed. Heads were decked and checked. New gasket kits everywhere. Never touched the transmission. Also switched out to a double roll timing chain 4 months ago.

Here's my issue: It starts and runs great, except when it shifts 1-2 and 2-3 then it gives me erratic/stalled shifting, unless I put the throttle into it a little more and shift it at 3k. It's been giving me a P0300 DTC with no other codes. Double checked the timing to make sure I wasn't 180 out or a tooth off. New plugs, wires, cap, rotor, TPS.

When I get up to freeway speeds (55+) on level or downhill at partial throttle, it feels like it's misfiring/ surging/ sputtering. Doesn't do it going uphill or with no throttle/ coasting. Doesn't do it under 55 mph. It's using a horrendous amount of fuel as well.

One time thing: Tried taking it over 60 mph, and the 4 Low button started flashing, so I quickly backed off the throttle and it quit.

I'm hearing stuff about the distributor being bad?, but I'm not seeing any excessive wear on the gear and everything seems tight.

I've stumped my mechanic friends (one is even ASE certified on GM's) so I'm turning to you guys.

Got the pump in and gettin good pressure but my uncle thinks it need a injector cause he said its loadin up and runnin very rich what namebrand injector should i get?

you have to or should replace the whole spider. look at rockauto.com. it will be an upgrade and will give you better peformance and mileage