Well, last year my car developed a stumble/miss. I repaced the plugs as it was easy to do and it did help the car run better, but I was still missing from time to time and could fell a slight miss in the upper RPM range. The stumble was very noticeable under a light load and would take a good 500 RPMs to go away. I usually most pronounced at low RPMs.
I did all the regular stuff, fuel pressure check, plug wire check, fuel filter replacement, vacuum line checks, secondary vacuum check, MAP.
The service manual recommend starting that car and while it was at Idle pull the spark plug wires one at a time. They all had a RPM drop (had EASE running) except #2, I also noticed that the spark was very weak on #2. On the other wires I could hear and see the spark inside the wire.
That was last year, fast forward to today
My car just rolled over 30,000 miles so it was due for spark plug wires. I pulled the plenum and replaced the wires and a faulty fuel canister purge solenoid. I put in Taylor 8mm red wires and four new AC Delco coils. I tested that resistance on the coils and three were the same and the coil for the #2 cylinder test quite a bit higher. I also tested the resistance on the fuel injectors which all tested either 8.3 ohms or 8.4 ohms. Put everything back together and went for a test drive.
Things are much smoother (and I thought it was smooth before). The miss it gone and so is the stumble. The car has zero stumbles under load. Looks like the problem has been fixed. Woohoo!!! :D
Pulling the plenum was no big deal, pretty easy to do and did not take very long. Getting it back on too a little longer but I would not hesitate to do it again if needed. Why do people get scared of working on these cars? I though I would be but with a service manual and this forum things can be pretty much tacked by any basic home mechanic that can turn a wrench.
Re: Plenum pull and stumble finally fixed (Aaron71771)
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Pulling the plenum was no big deal, pretty easy to do and did not take very long. Getting it back on too a little longer but I would not hesitate to do it again if needed. Why do people get scared of working on these cars? I though I would be but with a service manual and this forum things can be pretty much tacked by any basic home mechanic that can turn a wrench.
I know exactly what you mean. It looks intimidating until you actually do it. Then you're like, "Hey that was pretty easy". And as you said having a manual and the forum really helps out. It gets easier the next time you do it. And the next and so on. At SGC last year Aaron and George pulled the plenum off of George's car. That was the first time I saw it done. They had that thing off of there quick and clean.
It's nice when you go in ther on a mission and get the job done. Glad to hear you got the car running smooth.
Pulling the plenum was no big deal, pretty easy to do and did not take very long. Getting it back on too a little longer but I would not hesitate to do it again if needed. Why do people get scared of working on these cars? I though I would be but with a service manual and this forum things can be pretty much tacked by any basic home mechanic that can turn a wrench.
Glad to hear that your problem is all fixed now! I actually find disassembling a complete LT5 is much easier than an L98.
Re: Plenum pull and stumble finally fixed (MrCrowley)
It always looks intimidating until you start to tear into it.
I enjoyed tearing mine down the only thing that I even had a slight worry about was taking off the cam covers....
even then it wasn't the removal but the installation that had me a bit worried that damn sealant :D
Re: Plenum pull and stumble finally fixed (phrogs)
Looks like a lot of us are fixing our "hesitation" problems lately. Glad to hear that. I know mine was driving me nuts.
I Don't have any concerns about working on the "complex" (like so many people seem to think) LT5. Hell, I am sort of glad I had the hesitation problem. Now I feel like I could do anything on my car.
Re: Plenum pull and stumble finally fixed (Aaron71771)
have you had the injectors tested, just went thru mine and found that three were bad,replaced them had the rest flow tested, put back together,WOW what a difference, I but the car two months ago,it must of been running bad eversince i decide to look into it a bit closer i found #2 cylinder not getting fuel because the injector only ohmed out at 1.96 ohms, this car really flys now,i bought reman injectors for 45$ each for primary anyway this was my fix to get the BEAST running again
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Plenum pull and stumble finally fixed
