I have been making lots of posts on this subject of late and I am getting closer to identfying the problem.
Around the beginning of december my car began chugging and jumping through the RPM range. It also idled poor and lacked power. We thought maybe ignition. Well, I pulled the heads the other day (while doing my cam shaft) and had a cracked plug and one of my ignition wires had some small cracks in them in various places. Could that have been it? We also checked the TPS, that was adjusted and the car was still chugging. Also, in doing the cam swap I noticed that the timing chain had a good 1/2" of play on both sides, could that have been it? Also, my cam had some small indentins on the lobes in the wear patterns, could it have been that? We thought it might be a blown head gasket, but both head gaskets were fine. My O2 sensor tip is totally black, so I am getting a new one, could it be that? Also could it be a clogged coverter? Or anything else?

So, is it:
clogged cat, o2 sensor, broken plug, wires, timing chain?? or somthign else?

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

 

Um, YES! All of those things could easily cause all your problems. Get some new wires, plugs, cap&rotor and a new O2 on there asap. You can have a muffler shop check backpressure on your cat for about $15. If you still have problems you might want to look at that timing chain. Good luck.

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Base: 89 Iroc-Z LB9 auto 2.73 posi
Exh: 3" Dynomax muffler, 3" Pipe in place of cat
Ign: GMPP 8MM wires, Accel cap&rotor, AC Plugs
Fuel: Cleaned and flow-matched injectors, afpr, !air pump&diverter valve
Sound: Clarion deck, Kicker speakers and amps
Suspension: KYB Shocks, BMR Strut Tower Brace
Misc: TB Bypass, Synthetic Oil, Flexlite Transmission cooler,
free mods, flow tech headers on the way,
engine swap and 4th gen seats in the works...

 

or you could check the cat yourself with a vacuum gauge. hook it up to manifold vacuum. run the car up to like 2500RPM's watch the gauge if it starts to drop off then you have a serious exhaust restriction.

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have a beat to hell 87 GTA 305ci 700r4
t-tops,recaro,honeycomb wheels,digital dash
paid $600 at a junkyard for it (i had to save it)

 

Okay, what does a vaccum gauge cost?

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 Hot Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

7.5" 10 Bolt with 3.42s soon to come!

 

um, vacuum gauge is probably like $20. if you live near a pepboys that has a loaner tool program you can "borrow" on for free. you just put a deposit on it and when you bring it back they give back your deposit


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have a beat to hell 87 GTA 305ci 700r4
t-tops,recaro,honeycomb wheels,digital dash
paid $600 at a junkyard for it (i had to save it)