97 Blazer with High Idle when MAF unpluged and rough idle when pluged in at startup

[ndgely]

Hello All,
I have a 97 Blazer with High Idle(900-1100 RPM) when MAF unpluged and rough idle when MAF pluged in at startup. I was having issue with it starting up, I had to pour GAS in the carb in order to start. I was suggested to replace the Fuel Pressure Regulator. Once I did that, I have the rough Idle at start where I cant even backup without it turning off. What I discovered if I Unplug the MAF the car startsup but idle very high. If i leave plugged in the idle varys from high to low then becomes rough.

Any ideas would help. 97 chevy blazer, V6 4.3. So far replaced fuel pump,fuelfilter,battery,ignition switch,MAF(bone yard) and fuel pressure regulator.

[old_master]

Is the SES light on? If so, what DTC's are in memory? Have you checked fuel pressure and leakdown?

[ndgely]

last code I had pulled was P0174 to lean prior to fuel pressure regulator. I have not checked after installation.

[old_master]

Pouring fuel in to get it to start, is a classic symptom of low fuel pressure. Low fuel pressure will also set the P0174, and cause a rough idle.

Key on, engine off, fuel pump running, fuel pressure must be 60psi to 66psi. After the fuel pump shuts off, pressure must remain above 55psi for 3 to 5 minutes. Post your results.

[ndgely]

Pulled codes, now I have P0102,P0507. I pulled out the IAC(sits on bottom right of carb) and noticed the tip was cracked is this normal because how would it screw off to clean.

[BlazerLT]

Replace the IAC, replace the MAF.

[mike2004tct]

I'd probably replace it too.

Do you have a local Library near-by.
If so, go and look up the ohm range the IAC should put out.(if you have a ohm/multi-meter).

A couple of the repair manuals at my library list these types of specs.
Saves the cost of throwing money at the thing (which I've done quite a bit of)