Truck, 1500 Sierra Classic, 5.7L Vortec. 210,000Miles
At 190,00 I pulled the heads and did a top rebuild. At the time I replaced the distributor. Has been running great in till today.

Truck started with a bit of hesitation, usually starts right up. When I attempted to accelerate there was even more hesitation. Things went away and I was off to work.

I had a top on the way to work and when I turned the truck on same thing. I noticed that there were temporary lapses in power. Lots of hesitation. As I got to high RPM there was a hard thud sound coming from the engine bay (Misfire?). This happened each time I started to go fast. I say "hard" thud because it felt like i hit something small. I lost power at the sound of the thud.

I took it to autozone to have the codes read and they to me:
P0340 Camshaft Position Sensor Circiut Malfunction and
P0102 Mass of Volume Air Flow Circuit Low Input

I had to drive the truck home on the highway for around 40min. When I tried to go fast I heard the thud. I drove the whole way going about 40. Sometimes during start and stop idle would be rough and when i tried to accelerate there would be a loss of power.

Getting home I read the codes again... this time I gained 2.
Stored:
P0340 Camshaft Position Sensor Circuit Malfunction and
P0102 Mass of Volume Air Flow Circuit Low Input
P0441 Evaporative Emission Control System Incorrect Purge Flow
Pending:
P0203 Injector Circuit Malfunction


I do not know how to connect these error code or where to start on this...
and suggestions?

 

Problem Solved

Because of the P0340 Camshaft Position Sensor Circuit Malfunction I pulled the distributor and got it replaced under warrenty. I cleared my codes and tried to start it.

After starting same symptoms but now, the only two errors I revived were P0340 Camshaft Position Sensor Circuit Malfunction and P0102 Mass of Volume Air Flow Circuit Low Input.

I googled these codes at the same time and was directed to this web site (Sparky's Answers: 1997 Chevrolet S10 Blazer, Codes P0102 and P0340).

Turns out it was a the ENG- 1 fuse. Replaced it, cleared my codes and now everything is running fine.

Now... if only I knew why the fuse blew in the first place.