I have a money pit, I mean 97 Blazer 4.3L with 260k miles. Recently it started to have some hesitation in it. First noticed it while on the freeway, the car seemed to stumble a bit and the RPMs would flutter 100RPMs or so. Now it is experiencing hesitation when accelerating normally in first or second. It continues to flutter at high speeds as well. Looking for advice on what to try working on first.

Thus far we put a new air filter in and cleaned the mass airflow sensor. removed and cleaned the throttle body. Replaced both O2 sensors. Added trans fluid because it was low. Not sure where to go next.

The fuel injectors/spider was recently replaced by the dealer about 4 months ago.

Some things people online were suggesting were EGR valve and checking all vacuum lines. Anyone have a diagram of the vacuum lines for a 97? Thanks for any suggestions.

 

Drove it today and it was fine until the car warmed up to normal temp.

 

I had similar problems back around 140,000 miles. It turned out to be my catalytic converter.
I never got any Codes. Changed it along with all 4 Oxygen sensors and it has been running pretty well since. With 260,00 miles, and no maintenance records I think you would have to be a pretty good mechanic to figure things out perfectly. I am happy to see that you can put that many miles on a 97 Blazer. I plan to do the same. Good Luck.

Mark K

 

Thanks for the reply Mark. When you had to change your cat was your problem only showing up when the car heated up to normal temp? That's what has me most puzzled about this problem. The hesitation doesn't show up until after ten minutes or so of driving.

 

I had the same problem with mine. Never did figure it out but from whate veryone told me it could be a huge range of problems. Ranging from a simple tune up to a complete new distributor. Mine was doing it round 2500rpm range until it shifted into 2nd gear. But only when I wa sin O/D. If I threw it into 3rd by mistake then it wouldn't do it.

(my shifter I assume is like everyone elses but it goes P-R-N-OD-3-2-1. I assume everyones shifter in these blazers is the same but my bro told me some have a D and OD)

What i did pretty much was unhooked my battery for 1 1/2 hour. While it was unhooked I removed and cleaned my maf sensor and checked the number 1 plug to see if it was filed, burnt, etc..

After I hooked my battery back up the hesitation was gone and my ses light turned off. but the problems with mine started after it had rained pretty hard for a few days. My SES light did NOT turn on at first either. It turned on a couple days after the hesitation began. Has it rained or gotten a lot of moisture where you are recently? If it has then maybe its just some moisture got under your d. cap.

If nothing else, have you done the tune-up of it lately; plugs, cap, rotor, coil? If not then start there. Possible that your fuel filter can be clogged.

These are just things people have told me to check out. So i pass on this wisdom to you in hopes it helps.


And I agree that these are a money pit after they reach over 100k miles hahaha

 

After looking at a few of your guys mileage on your 97 Blazer gives me great hope. I only have 160,000. I might be luck enough to get another 100,000 sweet.

 

Spark plugs, cap, rotor, coil and the fuel filter have all recently been replaced within a few months. The filter only a week or so ago, that was one of the first things I did. It also had the intake manifold gasket replaced because it was leaking and when we did that ourselves we some how clogged the injectors so it went to the dealer and got a new spider injector put on.

I have also check the vacuum lines to the best of my knowledge I checked them all, but if someone has a schematic for them that would be great.

Any ideas of where to look next?

 

Changing the cat made a huge diference in mine... She runs great again... By the way Senshi09 my blazer has the P R N OD D 3 2 1 shifter so I can say for certain that they do exist.

 

Sure sounds like a cat problem to me as well.

OD D 3 2 1 would indicate that you have 5 forward gears...

The '96-'97 clusters typically had OD, D, 2, 1 while the 98+ have D, 3, 2, 1.

 

Took it to the muffler shop for a pressure test of the cat today and they said it was fine. Bummer I was hoping that would be it. Expensive to replace but at least I would have it running right again.