So my 94 full-size 4x4 blazer is running a bit rough and I haven’t. Even able to figure it out . I’ve replaced the alternator still running like ****. So I replaced the fuel filter still ****ty. I pulled the TBI off cleaned it out real good made my own gaskets put it back on . After the 2 try it didn’t spray fuel everywhere under the hood. I thought for sure it would’ve fixed it but nope . So I thought maybe the gaskets I made weren’t good enough so I bought new gaskets still ****ty. Once I had the TBI all on with new gaskets and all cleaned up and installed properly I started it up and listened to the injectors I thought they sounded like they were spraying a little funny but it wasn’t both of them just the one so I replaced . But nope still didn’t solve my mystery. I ran some injector cleaner nothing . I just can’t figure it out so I’m like WTF! If anyone has an idea what the problem might be please share with me . I’m really happy with the gas mileage I’m getting right now but the power it’s lacking is so annoying . It still is running but not great it has a really hard time accelerating. Thank you for taking the time and reading and a double thank you if you have a suggestion or pointers anything that might help.

 

Have you cleaned the MAF sensor wire? Checked the timing with the computer unplugged? Trying to think of stuff without using the parts cannon. When were the distributor cap, rotor and plugs replaced last? Have you check fuel pressure to the TBI? How is the air filter?

 

Ajbert thank you for your helpful advice. The first thing I did was test the spark on the plugs . That’s exactly what I thought at first that I had fouled a plug or so that’s exactly how it felt when I was driving it but it’s weird as I accelerate it cuts out really bad the more I accelerate it goes even faster but still hesitant but it goes. I just hit the secondary and it really picks up and goes which is weird to me, it uses half the amount of gas is normal, but it takes longer to get there if that makes sense . I haven’t tested the fuel pressure at the TBI. I didn’t replace the fuel pressure regulator on the TBI only because there’s no black smoke coming out the exhaust. And no engine light on. I went to smog it. They told me that the catalytic converter was going out. I’m wondered if maybe that has something to do with the issue I’m not really sure. I did look at the cap and rotor and rotor looks fine. The cap looks fine. I haven’t checked the timing yet yyyy

 

AJBert has given you good advice, including fuel pressure. I will add the possibility of excessive exhaust back pressure from a failing cat as a possibility.

George

 

My thoughts on the cat is it will run good at low speeds/rpm, but will start to bog down at higher speeds/rpms. That is what happened when I had to replace my cat.

 

A couple years ago when I took it in to smog it they told me I’m gonna most likely need a new cat soon . And I’ve been hearing a rattling sound underneath the blazer . Well today I looked and shook the cat and sure enough there are chunks most likely carbon chunks rolling around inside my cat . Perhaps something got lodged somewhere causing this problem would something like that make this sort of an issue?

 

Poor performance/misfires will certainly ruin a catalytic converter, and clogged converter will reduce performance even more. But if you don't find and fix the reason for the converter failure, it will repeat. Converters don't wear out - they are damaged.

You can pull an O2 sensor out and see if performance improves (on very short term) to see if the converter is plugged.

 

So I started the blazer and crawled underneath to listen to the noise that’s been getting louder and louder and it’s sounds like something rolling around in the catalytic converter. Long story short I cut off the cat now there is no more rattling noise . The contents of the cat was in like 3 or 4 different pieces . Once I had it off the blazer I couldn’t locate the exhaust clamps so I had to drive it from point a to point b and holy **** was it loud . It was a bit concerning because it was still sputtering a bit . So I guess I won’t know exactly the outcome until the cat is replaced by a new one… stay tuned