Hello, I have an 01 blazer that I recently brought back to life, I've changed the fuel filter, battery, air filter, oil filter and oil, pcv valve, and the vent valve solenoid as it was throwing a code. Ses light is off now.

When the engine is cold, it runs fine, shifts fine and everything. But once it heats up to operating temperature, if you push down too far on the accelerator, it sounds as though the engine is dying, and will cough or sputter. Thinking it was possibly just the Trans slipping, I brought it back home after a 10 mile test drive after replacing the vent solenoid, checked the trans fluid, added a quart, put a bottle of Lucas injector cleaner in the tank and filled it up. Brought it back home again, with the same issues. Let it run a little to try and get the injectors cleaned out. Got in it to head out and it stalled on me three times. Got it started back up, popped the hood, manually moved the throttle by hand, and it started to make a popping sound every now and again from the drivers side of the engine bay. I've read timing can effect this, or a bad egr valve as well as some times a MAF sensor. Upon inspection of the MAF sensor, there are some spots where the screen inside is slightly bent. Would this cause the issue?

Just looking for ideas and thoughts. On my way home yesterday, I had it up to 55mph, if I put my foot down anymore than to keep it at 55, or while going up hill, it would just lose speed and do nothing. I had to regain my speed down hill and hope for the best. It stalled 1/4 mile from my house. Started it back up and limped it the rest of the way. Gotta go back to work tomorrow, and can hopefully have the problem resolved by then, otherwise I'm screwed and may lose my job.

When i changed the fuel filter a while back, there was black sediment coming out of the old one. Another thought is the filter is plugged again (new filter). But I'm not sure that would cause the popping noise.

Thanks so much in advance for input.

 

1. if you have a scanner with live data, does this transition from running good to running like crap occur as soon as the system goes from open loop to close loop fuel control?
2. Can you graph the O2 sensors?
3. What are your four fuel trims at idle in park?
4. you’ll need to do the fuel pressure leak down test

George

 

1. Only when it's hot out or it's hot in the engine bay, it doesn't matter if it's open or close loop.

2. o2 sensors checked out fine

3 and 4. Fuel system checked out fine.

Bonus. Checked the vacuum system, and that checked out as well. the egr passed as well. Really thinking it's the ignition coil at this point.

 

I have a 98 Blazer myself. 103k. I noticed a difference in close/open loop operation when live scanning (Used BlueDriver). Obviously going up big hills will wear you down. It may be just be me and my perception but I'll notice performance oddities when it's really damp out/raining, and also when it's scorching hot/high humidity. Acceleration primarily. Not enough to fully differentiate it all and itemize it. I'm only getting about 200miles +/- on a tank of gas too. I have some vacuum leaks I'm sure of.

I've only had mine in operation on the road for about 3-4 weeks. Food for thought though. When I procured the vehicle, I immediately put Techron High Mileage fuel treatment in, topped it off with gas, and added Slick 50 High Mileage treatment to the oil. The vehicle ran like crap for about 50 miles, it was rough. Then it was like the clouds parted, angel trumpets played, and the sun came out.

I'm no mechanic and can't offer any solutions or ideas, but some observations as a Blazer newbie. Be careful with the rabbit hole of knowledge. I've learned so much about the Blazer platform and the ins/outs from this forum. It's enough to where you want to replace anything and everything. I started learning so much that I was panicked. Anyhow, thoughts from a newbie.

This is my first post on the forum. There are some amazing knowledgeable people on here. This forum coupled with YouTube is just mind boggling in all the things to know. Anyhow, cheers!

MG

 

I've learned a ton from your articles and posts George. This forum has become my Wikipedia. Thank you so much!! You and Christine, exceptional knowledge!!

 

I guarantee it will get me to work tomorrow, and possibly back, considering it won't be almost 100 degrees out. Problems peaked when it suddenly slammed into the upper 90s.

 

Get it hot and running like crap in the dark, then park and run at idle. Mist the ignition system with water and look for arcing, including around the coil.

George

 

dude I tried to get it running like crap today. It had a rough start this morning, but ran great all day. Changed nothing... wtf? Lol

I even shut it off a few times and started it back up. Ran fine. So confused

 

Intermittent problems can drive you nuts. Travel with your water mister and drive in the dark a lot.

George

 

I'll probably wind up getting a spark tester and go from there honestly. I need to add to my box anyway lol. It's not quite overflowing enough