Help? Weird Idle thing...
Thread Starter
Instructor
Joined: Jan 2006
Posts: 223
Likes: 14
From: South Florida
Help? Weird Idle thing...
Today I replaced my plugs. Installed Bosch Platinum. Checked the timing and it was at 8 degrees at idle with vacuum advance disconnected. Put everything back together, took the car for a ride and it seemed to run great. Got back to the house and I noticed that when in park the idle seemed a bit rougher than before the spark plug change. Originally the car had the champion cheap plugs in it and as I said, replaced with Bosch Platinum.
Anyway, I advanced the timing to about 9 degrees and the idle seemed to improve a bit - don't want to over do it there. Car still runs ok when driving - just at idle still seems a bit rougher than before the plug change. Anyone have a clue what could have caused the idle to go from smooth and steady to a bit rough and unsteady after a plug change? I am also seeing a slight fluctuation in the tachometer at idle - maybe not quite 100 rpms or so but still "wiggles" a bit with the slightly rough idle.
By the way, it almost acts like a small vacuum leak but I can't find one anywhere, and as I said, this did not start until I changed the plugs...
Anyway, I advanced the timing to about 9 degrees and the idle seemed to improve a bit - don't want to over do it there. Car still runs ok when driving - just at idle still seems a bit rougher than before the plug change. Anyone have a clue what could have caused the idle to go from smooth and steady to a bit rough and unsteady after a plug change? I am also seeing a slight fluctuation in the tachometer at idle - maybe not quite 100 rpms or so but still "wiggles" a bit with the slightly rough idle.
By the way, it almost acts like a small vacuum leak but I can't find one anywhere, and as I said, this did not start until I changed the plugs...
Last edited by Eric79-L48; Feb 11, 2006 at 02:48 PM.
Thread Starter
Instructor
Joined: Jan 2006
Posts: 223
Likes: 14
From: South Florida
Originally Posted by panchop
i'm sure you already did it but did you recheck the gaps on the plugs. might also want to make sure the boots are snaped on all the way and not justsitting on top of one of the plugs.
Last edited by Eric79-L48; Feb 11, 2006 at 07:13 PM.
Intermediate
Joined: Feb 2006
Posts: 36
Likes: 0
spark plugs
Bosch plugs are the problem...GARUNTEED!!!
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
Thread Starter
Instructor
Joined: Jan 2006
Posts: 223
Likes: 14
From: South Florida
Originally Posted by bigblokvette
Bosch plugs are the problem...GARUNTEED!!!
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
opinion, if I go to the store today, get me a set of Autolite plugs, gap them and install them this problem will go away? I am willing to do it - but I would hate to waste another $20 or so. You have seen this before? What is the cause? I mean Bosch plugs may not be "the best" but they should work shouldn't they? Would you mind explaining just a bit more just for my information?
Instructor
Joined: Mar 2003
Posts: 195
Likes: 0
From: Eagle Wi
Originally Posted by bigblokvette
Bosch plugs are the problem...GARUNTEED!!!
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Instructor
Joined: Jan 2006
Posts: 223
Likes: 14
From: South Florida
Originally Posted by bigblokvette
Bosch plugs are the problem...GARUNTEED!!!
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
Melting Slicks
Joined: Jan 2003
Posts: 2,713
Likes: 31
From: Shreveport LA
LA Events Coordinator
Originally Posted by bigblokvette
Bosch plugs are the problem...GARUNTEED!!!
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
Get rid of them!!!!!! buy autolite, or NGK---
Believe me I sell them for a living............for 13 years.
AC delco sounds good, but the above is better for carb. engines, they run a litte hotter, and don`t foul as much.
I also tried the Bosch plugs....car idled terribly! Changed to AC Delco...car ran perfect.
Last edited by vetteguy75; Feb 12, 2006 at 09:43 AM.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,502
From: Little Rock AR
You changed the plugs and the car starts to act up. The plugs (or more specificaly the new plugs heat range) are the likely suspect. Some times I think fouled plug problems are more common than we want to believe. 
Proper heat range is way more important than brand name or price.
I prefer Autolite plugs ever since they fixed a fouling problem I was having about 20 years ago. They seemed to stay clean longer than the others so I have stayed with them. A/C Delco are OK but I go for the Autolites when I can get them. Autolite seems to have a wider heat range.
-Mark.
Proper heat range is way more important than brand name or price. I prefer Autolite plugs ever since they fixed a fouling problem I was having about 20 years ago. They seemed to stay clean longer than the others so I have stayed with them. A/C Delco are OK but I go for the Autolites when I can get them. Autolite seems to have a wider heat range.
-Mark.
Thread Starter
Instructor
Joined: Jan 2006
Posts: 223
Likes: 14
From: South Florida
Originally Posted by vetteguy75
I also tried the Bosch plugs....car idled terribly! Changed to AC Delco...car ran perfect.
big time!! It is amazing how a different brand of spark plug can make such a difference...thanks all for the help!! My L48 is once again happy happy, joy joy!!
