My 1986 S10 Blazer (2.8L V6 4x4) has been giving me problems for the past month and it has steadily gotten worse.

When I bought this truck it needed a whole new exhaust. I was driving around with the rusted out exhaust as I did not have the money to fix it. Eventually I replaced the catalytic converter in December.

The truck was running beautifully all summer and fall, however when January rolled around it’s been shaking like a leaf and stalling constantly. It also surges at times will coast at 40km/hr. The idle is all over the place. When I come to a stop the truck shakes violently, the belts squeal, the battery voltage drops, and finally the car dies. It will run if I continue to give it gas. Weirdly, enough it feels normal at highway speeds.

It started while I was on a road trip. I stopped for gas, filled up, and started the truck. It idled rough, the SES light came on, and the smell of fuel was coming from the exhaust.

I had it towed to a local mechanic who checked all the vacuum lines. He recommended that I have the IAC and TPS replaced. He also told me my new catalytic converter was burnt up.

I had the IAC, MAP, and TPS replaced. And it ran again! Finished my road trip without any more stalling. However, a week later it all started again.

I had another mechanic adjust the TPS to the correct voltage and he did an Idle relearn. But alas it kept dying.

I took it to another mechanic who changed the fuel filter and fabricated a new fuel line as it was damaged when the filter was changed. That helped for about an hour before the problem returned.

Since then the stalling has become such an issue that I’m unable to drive it safely.

I pulled the codes and got 32 and 33.

What are the common causes for this problem? What diagnostics can I suggest to a mechanic? I want to avoid firing the parts cannon at this and have this issue properly diagnosed.

Any help or suggestion would be much appreciated!

 

This is a shot in the dark: You said you were told the catalytic converter was burned up. Did you do anything about it? Could it be plugged? Perhaps the muffler is clogged? Do you have a good amount of pressure at the tailpipe?

 

Haynes manual says code 32 is EGR. 33 is MAP. Were MAP vacuum hoses also replaced and are connections at ECM good? You didn’t mention any work involving the EGR so deserves consideration.

 

Oh yes, the EGR. I had to clean mine on my 92 4.3L many years ago. A chuck of carbon got caught in the valve preventing it from closing.