When reving above 3000+ RPM's, the engine cuts back throttle and /or fuel, almost like a governer. Chnged the plugs and wires, no codes on the ODB II scan tool. Might be the emission control sensors, or fuel pump? Suggestions appreciated.
On almost all gm cars after 96 the engines were governed to not free rev over 4000rpm. when in gear and power braking the rpms stay lower cause of the load on engine. when reving above 3500 rpms the computer cuts back the timing and fuel to reduce engine damage if left to free rev. hop that helps.
i had a similar problem on a 97 chevy 1500 4x4 and it would work fine until you were under load at or above 3900rpms and then it would cut spark so as not to do damage to engine. my boss and i went through the complete ignition system and fuel system to no avail. we then hooked a engine scope to find the problem, when above 3900 the spark would shut off and we could see it on the scope. the module would ground the spark internally. tried different modules(all ac deco) and would act the same. finally contacted gm tech line and were told this is a safe guard built in.
×
1,765 views
Usually answered in minutes!
I understand the the on board processor will idle back at high RPM's, but the problem still occurs when driving and in gear with load. This is an automatic 4 speed. So I am note sure if the processor is to blame or some other sensor.
×