I have a 2001 Blazer that runs good until I hit 3000 RPM then it almost shuts off and starts having issues running and will not get over 40 to 45 MPH. I can turn it off and let it set for 20-30 minutes and it acts fine until I hit 3000 again. Someone said it could be the ECM, just wondering if that could really be issue or are they just trying to take my money..any help would be greatly appreciated.

 

Does it act as if the ignition is cutting out or it is starved for gas? Does it do this at 3000 rpm when in neutral or only when traveling? Does it work if you keep it out of overdrive?

 

It's like it's starving for gas, it has all new injectors. Only when traveling. Especially if you get up on the highway.

 

First thing you should do is put a fuel pressure gauge on it so you can see what the pressure is doing when the problem occurs.

 

One possibility is a clogged cat. It usually shows up when you hit the wall at 50-60 mph, not 40-45 mph. But it is easy to check and free. Just loosen the exhaust before the cat. and run it to see if you still have the problem at 40-45 mph.Take all precautions and find a desolate section of road to do this Be careful and see if the problem is still there.

 

Think I am going to try the fuel filter and checking the catalytic converter.. Thanks for all the advice. Hopefully it will fix the issue. Ready to get rid of this thing already...

 

After re reading your post, my suggestion about a plugged cat. may not be a good one since you say the problem goes away when it cools down for 20 to 30 mins. A plugged cat. shouldn't be dependent on cooling down. But it is still worth a check sine this test is quick and easy and doesn't cost a dime...except for your time.

 

I had a similar problem with mine recently that turned out to be a bad MAF. Mine wasn't really RPM-dependent, though. It was more of a throttle position thing. If I gave it light throttle, it ran fine, but if I tried to accelerate or climb a hill, it fell flat on its face. When it was cold, It ran fine. If you have a scanner that will give you live data, look at the MAF numbers. Mine would only read up to about 60 grams per second, even at full throttle. So the PCM only gave it enough fuel for that amount of air, which made it run super lean and set O2 and misfire codes. With the new MAF, the numbers were more like 130 grams per second under hard acceleration, and it ran much better.

Not saying this is your problem, but it would be worthwhile to put a scanner on it and check it out.

 

Take a look in the Forum 2nd Gen for a post 'No power and struggles above 30 mph'. OP was ussexplorer. Problem caused by a clogged cat. Page 4.


https://blazerforum.com/forum/2nd-ge...30-mph-100010/