1979 Intermittent 350 surging

jph · 05-04-2009, 09:09 AM

I have a 1979 Colorado 4WD Chevy Blazer with a 350 connected to a manual transmission. I have a nasty intermittent problem that occurs more frequently as ambient, but not engine, temperature increases. The engine has always running consistently cool.

Sometimes upon acceleration, especially in 2nd gear, the engine will cut in and out, as if a fuel starvation problem is occurring or spark is being cut off. However, it will idle fine, run at cruising speed in 3rd if I am able to play my way through it. In other words the problem occurs off the line from being stopped or sometimes when headed up a hill at low speed. If it dies, I can usually restart immediately and and always eventually often accelerate again okay. Then out of the blue, it will happen again.

Quick restarts is not a symptom of boiling gas so I don't think that's it and the problem never happened before regardless of ambient temperature. I have a new fuel filter and recent fuel pump, distributor cap, ignition coil and HEI spark control unit.

It appears that I have some problem in my emissions system, but I am not sure what would cause such intermittent problem (some valve?). Also, I have noticed recently that my idle is always high as if I first started the truck and will not reduce as it used no matter how long it is run.

Any input would really appreciated to avoid blowing unnecessary $'s replacing random components in the hope that this thing doesn't make my ride home from work a nightmare during this warm week.

thanks.

emilio garcia · 05-05-2009, 03:08 AM

sounds like you got a bad spark plug wire.if you got new wires get an ohm meter an check each one you could have high resistance in one of them it's has happen to me. as for youre high idle reset youre automatic chock but do it when engine is comletely cold. good luck and let me know.

05-04-2009, 09:09 AM	#1 (permalink)
jph Registered User Join Date: May 2009 Posts: 1 OS: Windows XP	1979 Intermittent 350 surging I have a 1979 Colorado 4WD Chevy Blazer with a 350 connected to a manual transmission. I have a nasty intermittent problem that occurs more frequently as ambient, but not engine, temperature increases. The engine has always running consistently cool. Sometimes upon acceleration, especially in 2nd gear, the engine will cut in and out, as if a fuel starvation problem is occurring or spark is being cut off. However, it will idle fine, run at cruising speed in 3rd if I am able to play my way through it. In other words the problem occurs off the line from being stopped or sometimes when headed up a hill at low speed. If it dies, I can usually restart immediately and and always eventually often accelerate again okay. Then out of the blue, it will happen again. Quick restarts is not a symptom of boiling gas so I don't think that's it and the problem never happened before regardless of ambient temperature. I have a new fuel filter and recent fuel pump, distributor cap, ignition coil and HEI spark control unit. It appears that I have some problem in my emissions system, but I am not sure what would cause such intermittent problem (some valve?). Also, I have noticed recently that my idle is always high as if I first started the truck and will not reduce as it used no matter how long it is run. Any input would really appreciated to avoid blowing unnecessary $'s replacing random components in the hope that this thing doesn't make my ride home from work a nightmare during this warm week. thanks.

05-05-2009, 03:08 AM	#2 (permalink)
emilio garcia Registered User Join Date: Apr 2008 Posts: 26 OS: mozilla fire fox	Re: 1979 Intermittent 350 surging sounds like you got a bad spark plug wire.if you got new wires get an ohm meter an check each one you could have high resistance in one of them it's has happen to me. as for youre high idle reset youre automatic chock but do it when engine is comletely cold. good luck and let me know.