Mystery Stumble...

[95BlackTahoe]

I got the rear end in the Tahoe, and now it is wonderful to drive. with one exception...after it warms up, it seems to want to "cut out" or stumble. I wasn't sure if this is trans or engine, but I am thinking engine as the tach drops. It seems to be only 1-200 rpm when it does it, but I have no idea what it is.

I plan on giving it a general tune up to see if that helps any, but i was wondering if anyone on here had that stumble issue...

Thanks

Shawn

 

[SunlitComet]

check cylinder misfire history for a problematic cylinder to start.

 

[retorq]

I've had stumble issues related to temp sensor and throttle position sensor. The only way I was able to tell was using a real time scanner ...

 

[SunlitComet]

Ooops, sorry just noticed it was a 1995 model so misfire history is not available but still think it is a misfire issue.

 

[retorq]

Ooops, sorry just noticed it was a 1995 model so misfire history is not available but still think it is a misfire issue.

LOL I was gonna say something but you are almost never wrong.

 

[YenkoZL1]

I like TBI motors, not too many electronics to deal with. Since the stumble happens after the engine has wamred up, it may be electronic. After your "tune-up" I would look into the EGR valve and then the O2 sensor. O2 sensor is a maintenance piece that can cause hesistation and stumbles. And like RETORQ said, the Temp senor can cause stumbling as well. Cheap part too, like $20 or so. It operates using a frequencey it sends to the computer letting it know what the operating temp of the engine is. If the frequencey is off it can actually cause the motor to run rich causing stumbles and hesitation.

 

[SunlitComet]

LOL I was gonna say something but you are almost never wrong.

Just a momentary lapse of reason here and there.

 

[tradercollector]

Random stumble dist

I got the rear end in the Tahoe, and now it is wonderful to drive. with one exception...after it warms up, it seems to want to "cut out" or stumble. I wasn't sure if this is trans or engine, but I am thinking engine as the tach drops. It seems to be only 1-200 rpm when it does it, but I have no idea what it is.

I plan on giving it a general tune up to see if that helps any, but i was wondering if anyone on here had that stumble issue...

Thanks

Shawn

I had the same thing happen. It was very sporadic and the tach dropped. I did a tune up still had a stumble once in a while. one day it was running fine........ next day would not start.

I had to tow it to the mechanic! It was the distributor, the gear on the bottom was as sharp as a razor blade and then it finally jumped timing when I shut it off one day.

The mechanic showed me the old one and the new one the new one did not have a razor thin gear on the bottom of it!

The 99 Youkon 5.7 is running good. I had to change the spark plugs after trying to start it for three days because I pumped so much raw gas gas through it because I was in denial that it wouldn't run...... it was running just fine ,anyway I had to put a fuel pump on it last year . nice rig even though everything that goes wrong cost me $400.00

 

[95BlackTahoe]

I think I may have found the issue...The distributor cap "points" on the top are rusty, as are about 4 of the wires. Whoever installed them didn't use that dielectric grease on them. I bet this will solve the issue. Simple tune up...Let's hope so anyhow.

Shawn