1997 Vortex 5700 Stutters/misses

[DieselDetroit]

Hey guys,

97 Vortec 5700 in a 2dr Tahoe. 200 miles.

The issues is at low load (under light throttle), the truck stumbles and hesitates and kind of jiggles around. This is also felt at cruising speeds, 65 MPH, also under light load.

When floored, it doesn't do this.

I initially thought a head gasket leak causing coolant to reduce the strength of a spark, but I did a compression test today

Cyl1: 192
Cyl3: 190
Cyl5: 190
Cyl7: 190

Cyl2: 188
Cyl4: 188
Cyl6: 208
Cyl8: 192

No bubbles in the rad cap, hose doesn't get hard, no mixing between coolant and oil, but I do remember seeing some orange crystals in the tailpipe at one point, also steam coming out of the tailpipe regularly, and it stinks, but it may be fuel? Could it be coolant? Would a compression test rule that out?

Not sure where to go next. I was suspecting the tranny? With respect to the motor, It has new plugs and I believe a new cap. No present codes as I just put in a new battery but a few months ago it momentarily ran like crap with the CEL blinking, unfortunately the battery has since then been replaced and the codes are gone. It only ran like that for about 5 mins.

Thanks,

 

[98 Nitro]

I thought I had a head gasket leak too, did the same tests as you same result. Then I read the vortec trucks are notorious for intake manifold gasket leaks.

 

[beardeddummy]

I would change dizzy cap

 

[Dave11]

I would change dizzy cap

10 times out of 9 the cap is bad

 

[beardeddummy]

10 times out of 9 the cap is bad

unless it's the cap.