Today my car started to go rough on idle, itīs shifting between 500-900 rpm. Itīs also kind of slow all the way when I accelerate.
The sparkplugs were recently changed and the wirings to and also the rotor+caps.
The car also smokes in startups, but i belive thatīs the valveseals thatīs leaking.
what could be wrong? Could it be the timing, and how do I adjust that?
The car is a stock 305 TPI Z28-87
thankfull for response.

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Z28 -87 TPI
white with T-roof
red interior with leather seats
Wagner Borg
all options

 

Did you check to see if the sparkplug wires are wired up correctly?

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1989 IROC-Z 5.7L
NOS 5151 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

 

Yes, the car have been running great until now.

 

Two thing that comes to my mind is the MAF and the IAC. Try disconnecting the MAF and start the car, does it run better or still as bad? If it runs better, you probably need a new MAF. If that doesn't make any difference, remove and clean the IAC and the IAC passages in the thtrottle body...... More suggestions anyone?

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ZaphodB a.k.a Carl Andersson - zaphodb@faxancruisers.org
'89 Camaro IROC-Z 5.7L TPI - Mods under construction :-)
Custom ARAP Chip Under Development/180 t-stat, Edelbrock TES Headers,
SLP Airfoil, K&N Filters, Accel 8mm wires, Relocated MAT, AFPR @ 45 PSI

 

I'd check for vaccuum leaks.
I had a craked hose at the fuel pressure regulator which caused some instability.

Also, if you have a vaccuum pump, check to see if the EGR closes fully. If it's partially open at idle, it will cause the motor to run rather rough.

Hope that helps

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Sat "IROCkid" Bimrah
1989 IROC-Z 5.0 L / 5 spd

 

I changed the TPS and the car now runs perfectly :-)