s_harrison_jr

I have a 99 SS with around 120 thousand miles on the motor, this motor is bone stock. Now for the problem, when I run the car up hard in RPM's say around 5k + when I get out of it is skipping like crazy. You drive about a mile taking it easy and it goes back to running normal just as smooth as can be. It has done this to me twice now. I do not hear any tapping noise or anything like that. Any ideas? I am thinking it may be a lifter either floating out or may trying to go bad what do yall think? Thanks for the help

GuitsBoy

iTrader: (4)

What do you mean by skipping? Do you mean missing?

Also, this is not advanced tech. Heck, it might not even be internal tech. Try general maintenance and repairs.

Domestic Demon

iTrader: (1)

Could be something with the Opti-Spark ignition system. With that many miles, it may be going bad. At those high RPM's, it may not be giving you sufficient spark, causing it to miss.

Just a guess, might want to check that out first.

fast98

iTrader: (16)

opti on a 99 ss? they stopped that crap in 97 with the lt1. how old are the plugs and wires? how about the fuel filter?

Domestic Demon

iTrader: (1)

Really?? My bad then, I though all the F-Bodys had opti-spark, from 93-02

GuitsBoy

iTrader: (4)

your sig says youve got a 98. 98's came with the ls1. your car disnt even have an optispark. Only the LT1's had an optispark. LS1's have an individual coil per cylinder.

s_harrison_jr

Right all LS1 are coil on plug set up. New wires about 2 months old plugs replaced at the same time. I have not replaced the fuel filter but even a bad fuel filter would not cause it to skip only after a hard run and then start running smooth again.

GuitsBoy

iTrader: (4)

Not necessarily true. Sediment could be clogging the filter element during heavy flow, then it could percipitate back down to the bottom after a little while during low flow. Id pull the plugs and check for cracks, make sure all the wires are on correctly and fully seated. If theyre not fully seated that can cause issues like this as the motor vibrates them off at rpm, then a few minutes later they contact the electrode again. I had a bad wire only affect from exactly 2500 rpm and up. I though it was a broken valvespring.

s_harrison_jr

The car has only done this to me twice. Both times I had run the motor up over 5k and when I slowed back down it is skipping (missing) like it is only running on 7 cylinders. A fuel starvation, clogged fuel filter, would not cause this problem. I have worked as a mechanic for several years before and currently am a store manager with a parts store, oh and I am ASE certified with parts. I just have never had any experience with this motor and thought maybe some of the gurus on here had either heard of this before or had it happen with them and could give me some guidance.

KENS_SS_4

carbon build up? dirty cooling passages? Oil blow by at high r's that tempararily fouls plugs that cleans it's self up after driving awhile? No codes, right?

Sounds like it is time to be a mechanic again!

s_harrison_jr

It is not setting the SES light but I have not had a chance to put it on a scanner yet to check for possible stored codes. The way it is acting I am kinda leaning towards a weak lifter but not sure.

'Trust'

iTrader: (24)

Not to sound rude, but totally blowing off someones suggestion when you ask for help isnt the best thing. If your ASE certified then get your hands dirty and figure it out. Cracked plug maybe?

GuitsBoy

iTrader: (4)

Seriously. I mean, he's ASE certified, yet he cant even start troubleshooting and diagnosing a miss? We all listed the very first steps that any mechanic, no matter how shade-tree, would start off with.

Please go fiddle with your car and check the easy stuff before asking us to take wild shots in the dark with little to no useful information, and no way to verify other than, "trust me, im an ASE".

s_harrison_jr

The only reason I asked on here was because I know that every series of motors has problems that happen to them with regularity and thought this might be one of them. That just by chance it might be something that happens to these motors because again this is my first dealings with an LS1 so I thought I would post the question on here and get opinions from some people who have had lots of experience with this motor, and I was not blowing anybody's ideas off. "Trust" the comment you quoted was not directed at the person who suggested the filter but at guitsboy who seems to think a clogged fuel filter will cause a car to skip. A clogged filter will give you a low power , or no power conditions and under extreme situations might cause a motor to studder or hesitate but it will not cause a cylinder missfire situation.

fast98

iTrader: (16)

first of all just throwing around things like im ase certified doesnt mean much, i am a master ase mechanic, so what it doesnt mean anything unless you can fix the car. and for a side note i have seen more then one fuel filter cause this problem. it could be a whole slew of thing you might never think of. basically just check the obvious, and maybe check out all your plugs and wires again. not saying you did something wrong, just saying i've done it myself and if you just replaced something. the first thing your gunna do is say "o well thats not bad i just replaced it" how about some more background on the car. and scan it for codes please

GuitsBoy

iTrader: (4)

Thanks fast98. I can build up engine, port my own heads, spec my own cams, and tune my own software... But since im not ASE certified in parts my opinion on the fuel filter clearly aint worth looking into. The frickin thing is probably 120K miles old.

It costs $8. Replace the damn thing already. Check plugs for cracks. Check wires too. All these things were brought up. If its not any of these, then we can speculate further.

KENS_SS_4

The lifters can not be "weak". They are for conversational purposes, "solid" with a very small distance of hydrolic dampening. They usually hang up in their bore or loose their hydrolic dampening.

Float is generally a spring problem. But lifter, spring, rocker assembly and valve problems generally have a tick sound to go along with them. You have already reported that there is no ticking noise.

Are your sleeves rolled up yet?

If this turns out to be caused by the mechanic that did your plugs and wires (you, right?). Are you going to report that to us?

I am currently under the impression that you haven't even opened the hood and checked the simplest things. Like the plugs and wires you changed.

Please don't get defensive, get busy!