91 s-10 blazer stalling/lunging around right turn

[BIGShorts]

I own a 1991 s10 Blazer, Tahoe package, 4.3 (NOT A VORTEC). 228000 miles. I have always taken very good care of it but this problem is killing me (not to mention everyone I have asked). The engine ALWAYS dies while going around a right hand turn and also while going straight. It doesn't stop running completely but the RPM's plummet, then go back up again. It lunges as if you had your foot on the gas and hit the brakes real hard every second or so. up and down, up and down. Esp. in a right turn/curve, it'll start to die, then I cut the wheel left and it quits. I can hammer it around a left hand curve and nothing at all seems wrong with it. Its hard to explain but its like someone is pinching the fuel line about once every second. Almost everything on the Blazer is new. Fuel pump, strainer, fuel filter, fuel pressure regulator, O2 sensor. All the tune-up stuff is in good shape (Plugs, wires, pcv valve, filters, etc... I took the EGR valve off, cleaned it up real good, put it back on with a new gasket and that didn't even phase it. I am getting absolutely no engine codes either. I have ran my own codes countless times and even took it to a professional who put it on a computer scanner and the guy said everything was fine. Any ideas??? Please help.

[BlazerLT]

Sounds like a short in the wiring.

Have you gotten the engine codes scanned?

[BIGShorts]

Originally Posted by BlazerLT

Sounds like a short in the wiring.

Have you gotten the engine codes scanned?

Yes I have had the codes scanned and nothing comes back. I had them ran by a professional with a digital scanner and I also did it myself. blinking 1-2's. nothing.

[BlazerLT]

Sounds like an electrical connection is bad.

Check the wire harness in the engine compartment and look for wires that have been worn through in the wiring harness.

[BIGShorts]

Originally Posted by BlazerLT

Sounds like an electrical connection is bad.

Check the wire harness in the engine compartment and look for wires that have been worn through in the wiring harness.

I checked all the visable wires as well as all the vacuum lines today. I also replaced the EGR solenoid. Nothing. Also, it drives OK when it is cold. But once it warms up it starts all that lunging stuff.

[goodtimepete]

Possibly the ignition switch???

[BlazerLT]

Timing
Fuel supply problem
Spark problem
O2 sensor problem

[BIGShorts]

It seems to have been the MAP sensor. I finally got a code to come up, 34, which is the MAP sensor. I replaced that, along with all my vacuum lines and so far so good.

[BlazerLT]

Nice, good to see it finally caught the problem.

Sometimes codes will take some time to set as the sensor fails.