Just wanted to see if someone could help with a problem I can't seem to fix.
I have an 88 350 that was a 305 tbi and I swaped to TPI. I have been working out most of the bugs but one I can't seem to get. When I drive the car it has a rough idle and also when I come to a stop and put it in park it idles around 1800 and wont go down till it cools down . The car runs ok but does have a slight miss at low rpm's . I have replaced cap,rotor,wires,plugs,maf,tps,iac,coil with new injectors (24lb) and almost all the sensors and checked for vacuum leaks also set the tps and iac and set the fuel press at 50 with the vacuum line unpluged .The car is mosly stock just headers, exhaust, gears and 52mm tb and a prom to match the currunt mods. I am going to make more mods but I would like to start with a good running car first. Any help would be appreciated . thanks

 

Try resetting the idle with the adjustment screw on the trottle body.

 

Think that would work? I will try it. The idle is good in gear (700) .

 

I tried that . it did not work, the screw does not even touch the bracket.

 

How's your timing?

 

Timing is at 6 with the wire unplugged.

 

are you useing an external tach to make sure its really idleing that high or useing the factory tach

if it was really idleing that high when you pop it in gear it would really be putting a load on the trans

my dads irocs tach is off and shows 1500 when 1st started then shows 800 in gear but really its 900 and 600 cold start and drops to 700 and 550 when warm but i checked with a external tach to see before i when searching for vac leaks and what not

 

could be a a faulty tach, one i have is a factory one, its 1k higher at all times. start, scanner reads 800, tach is 1800, ive learned to live with it.

 

I checked that already . the engine races high you can tell it's not tach . I am starting to wonder if I was sold a bad iac motor .

 

u should be able to adjust the iac, least set it to factory and it may help you narrow it down.

 

Ok back at this high idle still. replaced iac and still there. Not sure where to go now I have done tps,iac,maf, collant temp sensor,set timming,02, set fuel press and tune up. I have no vaccum leaks . I have reset that iac motor 10 times and it is ok for about ten mins each time than back to a 1500 rpm idle.

 

did you ever figure it out?

 

Mine is doing the same thing! Hope he comes back with a solution!

 

Has anyone come up with the solution to this problem. I have an 86 camaro tpi with the same issue! I've done so much research and it seems like no one has an answer. It's making me irritated as f***.