Trying again....Miss or Transmission?

[Ted B]

Hi Everyone,

I"m new at this and already I was indirectly asked to kindly post 1998 and older Silverado issues here. You guys must be the experts I'm looking for! I hope.... Anyhow, see if you've come across this or have any suggestions. Below is my original post with the follow up below it.

Hi everyone,

I'm a new user, first post and I hope someone will have some insight on my problem. My 1998 Z71 4x4 5.7 liter has been acting up lately. It has 106,000 miles.

My truck seems to miss or stutter, sputter, or basically run rough when either slowly accelerating (around 15 to 20 miles per hour) and/or cruising at or around 50 mph. It does not do it all the time and only does it when I slowly accelerate. If I romp on it or even accelerate more than a grandpa would it runs like a champ. Seems transmission related because it only seems to run rough until it shifts into another gear but does not feel like slippage. Once it shifts it runs fine. My friend thinks I need to replace the plug wires and it may be missing since I did not do this when replacing cap, rotor, pcv valve, and plugs a moth prior to this problem. He says it's not transmission related saying that it seems to have the same problem accelerating around 20 as cruising at 50 where my truck would be running around the same rpm. An O’Reilly parts employee tried to tell me it may be a transmission shudder and that two of his previous Chevy’s had the same issue and is not uncommon. He said its not harmful but recommended that I buy some transmission treatment fluid and it should stop the shudder. And finally another friend told me that it might be a vacuum leak that only shows up when cruizing where vacuum leaks would be more noticable than when you get on it.

I've changed the transmission fluid every 30,000 miles. Just bought AC Delco plug wires at lunch and will replace tonight and as mentioned above, I’ve replaced the cap and rotor and spark plugs but I have a funny feeling this is more than old wires. Anyone have any suggestions?

Update:

Last night I stoped at the parts store and used their ODB2 sensor deal. It threw only one code that said I have multiple misfires. I figured for sure it must be the plug wires. I slapped on the wires last night but it still did the same thing driving to work this morning.

Any suggestions?

Ted

[decoy86]

My 99 Tahoe just started doing the same thing. My wife hasn't complained about it yet... But I have felt it.

[skipr]

Is the DTC P0300? If so you need to use the step by step procedure to eliminate and isolate the possiblites. P0300 can be numerous things, evrything from VCM controls to mechanical moving parts.

[roonie]

i believe i have seen this posted question before.why dont you search previous posts.there are tons of old posts and im sure you will find the same question asked.just a thought.I have a 90 chev so things are much different.

[skipr]

Originally Posted by roonie

i believe i have seen this posted question before.why dont you search previous posts.there are tons of old posts and im sure you will find the same question asked.just a thought.I have a 90 chev so things are much different.

It is posted in different forum by same person, he was told to post here (by moderator) instead of silverado forum

[Fireplug]

Gm is have problems with the distributer shaft having to much play and causing the problems you seem to have.