oddscrounger

1987 IROC Z 305 TPI LB9 with Edelbrock shortys. Last July I replaced all plugs, wires, distributor cap and rotor… car was running great but I always had this stumbling/popping problem at takeoff, especially when engine was cold. A few weeks ago I posted a thread with a video of the engine running. Was making a clicking/ticking noise that would increase with RPMs. Took off the valve covers and some rocker arms were very loose on the passenger side. Tightened them down only enough so that the ticking went away; all the parts were well oiled, so that eliminates the problem of poor oil pressure/failed oil pump.
Engine was idling very rough at super-low RPMs and would die. I advanced the distributor slightly (I know you’re not supposed to do this) and of course now it idles over 1000 RPMs. I am going to remove the distributor and check for play or wear. I have correctly set minimum idle air speed in the past when the engine was running great. I have been getting a code 42 for a long time now.
Even after advancing the timing a little at the distributor the car idles super low again after it gets warm. It dies especially when I come to a rapid stop at a light or something. Rough start/rough idle/loss of power are my main symptoms. Also very disturbing symptom is the car shakes violently at low RPMs in higher (4-5) gears.
Any ideas from my super-experienced TGO brethren?

redneckjoe

id check the timing with a timing light, follow the correct proceedure if stock.
diagnos you code and repair that problem
see if that helps first.

oddscrounger

Isn't the timing on TPI vehicles determined by the parameters in the PROM? And car ran great for a long time even with code 42. However, the SES light has been pissing me off and I have been meaning to replace the ICM for a while now... why the hell would the car shake at low RPMs in higher gears though? And where is my EGR valve on an 87 LB9 engine?

oddscrounger

code 42 eliminated with new ICM... also replaced new o2 while I was at it... timing set back to base timing with EST disconnected. Still super choppy idle, running at like 50% power... clicking is gone since I tightened the adjusting bolt on the rocker arms but does this need a valve adjustment now? Also, my car bucks violently in 5th gear...

aremy10

iTrader: (3)

if you can, remove egr and block it off with a plate and gasket. see if problem stops. I would also clean out the throttle plate area, try sea foam job. clean iac motor etc, I just had the same problem with my old mans truck, ended up being the coolant temp sensor(by the water neck, not the 1 wire sensor for temp gauge) was doing the exact same thing. had to rev it up after replacing it till it cleared out and started running good , but thats what his ended up being. kind of pissed me off all the stuff i did to it to find that all i needed was a temp sensor. hope any of this helps

dads old blue 9

my guess is plug wire. lots of people tune up their car only to have problems a week later, usually they rout the plug wires differently and they get cooked because they were laying on a header or something. checking this costs nothing.

oddscrounger

I am going to give it a valve adjustment this week and at the same time I will check the EGR valve. Wires are high-heat resistant and zip tied away from my headers. I was having problems with the wires last summer.... I'll keep ya'll updated. Thanks for the random responses, thought this thread was dead

oddscrounger

ok had a broken valve spring.... just thought i'd check back in the the TGO world