I have had a 99 blazer for about a year and a half and it seems to have the same reoccuring problem.

About a month after I first purchased it it would stall while driving. The mechanic I had taken it to replaced the ignition module and it ran perfect for a couple months.

Next the alternator went (which was an easy fix because I knew what it was)

Next it would stall randomly and bog down until it would no longer fire up. I replaced all plugs and wires, rotor, fuel filter, etc ... and it worked perfect again.

Lateley it has been running fine except for the occasional Check engine light and service4x4 light. The only code I have been able to pull out of the computer is P1875 which I don't think is the cause of the problem now. (feel free to give input if you think it is related)

The last couple of days however it has started stalling again. It happens at anytime but generally more when it is idling. It does not sputter or give any hint at stalling and will start up right after. The engine sounds good and the transmission is fine. If it stalls while driving I still have dashlights and headlights but no power steering.

Besides the fact that I should never buy from this dealer again what do you recommend?

What are all the possible problems that could cause this? I am sick of dealing with it and would rather check it top to bottom myself rather than pay more money than the car is worth to have it taken to a mechanic.

 

im having the same problem my service engine soon light is on i jsut bought my 99 2dr blazer it just dies out when im driving i put a full tank of gas in it the other day and found out i have a leak so i got the codes read and she said i might need a new gas cap and a tune up but the guy i got the car from is giving me another tank and fuel pump

i was told the fuel pumps are a major problem on the blazers

 

Here's some info on the P1875 code:
Circuit Description
The four wheel drive (4WD) low circuit consists of the vehicle control module (VCM), a transfer case control module (TCCM) and the circuit wiring. The TCCM controls the 4WDlow signal on circuit1694. When the operator selects 4WDlow, the TCCM grounds circuit1694 and the 4WDlow signal voltage on the circuit changes from ignition voltage to zero volts. The VCM then compensates for transfer case gear reduction in the transmission output shaft speed (OSS) signal. The VCM uses the transmission OSS signal to adjust shift points, line pressure and torque converter clutch (TCC) scheduling.
When the VCM detects a continuous open or short to ground in the 4WDlow circuit, then DTCP1875 sets. DTCP1875 is a type B DTC.
Diagnostic Aids
Inspect the wiring at the VCM (Vehicle Control Module), the TCCM (Transfer Case Control Module) connector and all other circuit connecting points for the following conditions:
[*]A backed out terminal[*]A damaged terminal[*]Reduced terminal tension[*]A chafed wire[*]A broken wire inside the insulation[*]Moisture intrusion[*]Corrosion [/ul]
[*]When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change. [/ul]

 

After checking through most of the blazer I have it narrowed down to a couple possible problems.

Faulty crank shaft sensor

and

Bad ignition module.

If it is a crank shaft sensor problem would it show up as an error code in the computer? How would I go about finding and testing the sensor?

I have a strong feeling it is a bad ignition module, as the stalling conditions are remarkably similar to the ones I had prior to replacing it. The ignition module was replaced with an old ignition module which may explain why it has conked out so soon. How do I test to see if it is actually the ignition module? Without just going and buying a new one only to find it isnt the problem.