Hello, and thanks in advance for help or advice.

Vehicle: Late model 1995 Blazer 4.3 Vortec with 168,000 miles on it.

Problem started when it broke down when driving about 50 mph and it stalled out. Towed it home and it started later, but will only run until it warms up, and then it starts acting up, rpm gauge will start jumping around between 700-1200 rpms and then ocassionally jump up to about 1600 rpms and float there for about 5-10 seconds going up and down a hundred rpms or so. RPM gauge seems real sporatic.

I did find a leak in the fuel return line inside plenum and fixed that, and thought problem solved... no such luck.

Still has same symptoms as above, but I did get a code P1361 low IC curcuit (low voltage at module) I read code is #1 cyl. not toggling.

Anyway, I cleared code and tried to get it to fail again, and it did fail, but this time I got a different code. I got a Code P0341 with minimal freeze data.

Camshaft position sensor A -
Bank 1 CKT Range/perf

704 eng. rpm
Load value 3.1%
Coolant temp 188 F
Map 32 KPA
Short term fuel trim1 -2.2%
Long term fuel trim1 -3.4%
Short term fuel trim3 -49.3%
Long term fuel trim3 64.8%
Fuel sys 1 closed
Fuel sys 2 N/A

Could a bad cam sensor cause the low IC curcuit code ?
I have checked the connections and some of the wiring, and that was all good. I checked the ground curcuit on the ICM with a test light and that was good.

I do have cold freeze data from when engine was cold by unplugging the tps connector, if that will help.

Can anyone give me some advice on what to check next, and or what may be the problem ?

Thanks again in advance for any help I can get.

Sluggo

 

i just bought a 95 4.3 vortec also. i drive 40 miles each way to work after 30 miles it starts loosing power wont shift right and back fires. has 185k miles on it and i need to figure out how to fix it. when cold runs great once it warms up terrible. let me know if anyone knows what to do first. i have changed the fuel filter so far thats it. this weekend im draining the trans and putting a new filter in it.

 

https://blazerforum.com/forum/diagno...plained-28846/