Brandon91Z28

Need some help, I have a 91 Z28 with 350 tpi. Sometimes when I go to crank the car I hit the switch and the rpm's will only jump to 1000 then settle to 750 immediately. Normally the rpms go much higher then settle back down. When the rpms don't jump high as normal the whole car seems to not run right you can barely hear the exhaust at idle and it also seems really quiet while going down the road. Every now and then the car will just die when coming to a stop, and there is a very large surge when you start off, say from a light you mash the gas and it is like the motor almost dies and then it surges forward and will push you back in the seat. I haven't started checking anything yet but I am thinking bad plug, wires, cap, rotor, or maybe fuel injectors.

The car is turning on the ses light itermittently but I checked the codes and only 32 displayed, the egr is unhooked.

Any suggestions for a good place to start would be greatly appreciated.

Sonar_un

You are going to get a code 32 when the EGR is unhooked.

I would start with plug wires, plugs, cap and rotor. I am having a similar issue with my car, but most likely it will be ignition related.

After you do that, and still are having some problems, I would go ahead and check the timing, TPS sensor, and IAC motor. Get the throttle body cleaned up and those IAC passages cleared.

That should cover most of the basics.

Brandon91Z28

Thanks I'll give the norms a check and change and see if that clears it up. I actually cleaned the throttle body and iac passages not to long ago. I have checked the tps sensor before by jumping across and watching the voltage as throttle is applied, and ended up replacing although it has been a while. How do I check the IAC motor

Sonar_un

https://www.thirdgen.org/techbb2/sho...ight=iac+clean

Brandon91Z28

thanks that clears up any questions for the tps and iac if I have to go that far.

Hopefully after looking at the plugs wires cap and rotor it will solve the problem. I guess If I'm gonna take it all off to check it I might as well replace it

Brandon91Z28

What plugs, plug wires, cap and rotor are you guys running. I know that I have taylor 8mm wires custom with 90 degree ends on all because of the edelbrock tes. I also have shorty accel plugs. Looks like I'll be changing all of mine as you probably read above. It has been a while since any of this stuff has been changed. I recently started driving my car again because I sold my daily driver.

CrazyHawaiian

I've got a similar problem with my 89 IROC, went with MSD cap and rotor and wires, gonna change the plugs today. Another upgrade to think about is the MSD upgrade for the internals of the stock dist, I think its like $50. Unfortunately for me this didnt solve my problem and the troubleshooting needs to continue (checked air, fuel, codes, replaced TPS,replaced cap and rotor, led to checking timing, now suspecting a bas ESC or loose timing chain, time to bust out the DVM)

vernw

iTrader: (2)

Check the plugs for a loosened threaded on plugs wire cap. That's the only complaint I've found on the Accel shorty plugs, those caps alwasyseem to work loose. I've enn gone to tighteneing them with pliers before installing them. A loose cap will cause intermittnet misses that are a real killer trying to track down. You shouldn't have to ask me how I know this....

Brandon91Z28

are you talking about the little metal end on the spark plug. Because It seems like I remember tightening acouple of those when I installed the plugs

eXesiv|83ta

iTrader: (4)

I have heard that those accel plugs are overpriced and don't work that good. Try a set of NGK UR5 plugs. They are better quality and cost less. Just a suggestion.

Brandon91Z28

Are the NGK UR5 plugs a shorty style. I don't really have a lot of room on some of them with the headers

vernw

iTrader: (2)

Yep, those little screw on ends is what I'm talking about. They like to work loose in the motor.

The UR5 plugs are short plugs, but not as short as the Accels. I've used both w/o muc difference, but the Accel plugs give me a little more header clearance.

92HeritageT~Top

Ok, just a suggestion here...you say the EGR is disconnected, but is it still on the car? That is the excact same problem I had with mine, and it was because the EGR valve was stuck slightly open from carbon deposits. Mine was disconnected too....

When that happens, it causes all kinds of stumbling, erratic vaccum readings, etc. Especially at Idle or take off...

Take it off the car and completley soak the pintle, seat, etc. in Chemtool or Carb Dip. Since you aren't using it you could even throw the whole thing in a vat of the junk. Work the pintle etc. until it moves freely. Then put it back on the car.

I just totally took mine off the car...and made a block-off plate to go in it's place. Solved the problem completley.

Hope this helps!

Brandon91Z28

yeah the egr is still on the car. When it went bad I was afraid to take it off because I have already broken off one of the thermostat housing bolts in the manifold because it was seized I assumed that the egr would probably do the same. And let me tell you the thermostat bolt was a nightmare, I never did get it all out, had to go with a shorter bolt and some washers. Do you think that that might be the problem in the first place It will probably be this weekend before I can tear anything down. Since this is my daily driver now. Don't want to chance trying to take things apart after work because it always seems like I break something to fix something else. (THe only bad thing about working on 14 year old cars.)

Any way I can check that without taking off the entire air plenum.

eXesiv|83ta

iTrader: (4)

I have iron eagle heads with angled plug holes and straight plug headers and I don't have much problem with header clearance.

92HeritageT~Top

If you've never pulled off the EGR, I'd reccomend it. I can almost guarantee that is your original monster, lol. Just pull it off and clean it REAL good and see what happens.

If you are afraid of the bolts breaking...every day, maybe even twice a day, from now till you work on it...spray those freakin blots with anti-seize lube. You can get it at most automotive or hardware stores. Should help to break them loose.

And yeah, broken bolts are a real PITA, lol.