Okay boys & girls, y'all have gone through this, I know you have.
My car was having a bad stuttering/hesitation/hiccupp-ing problem for months now, I figured it was the Opti, typical story, right?

Here's what I've done so far, in this order.

New fuel filter.
EFI cleaned out.
New Opti & WP.

Those changes did make a big difference, and, it still hesitated between 1000-2000rpm when the engine is warm, so...

New MSD coil.

Actually that helped a bit as well, problem is still there...

SO...

New plugs & MSD wires, new O2 sensors.

Better yet, and, same symptoms.

Okay, either clean out the TB/IAC valve or EGR valve...

Tried to change the EGR valve, couldn't do it, too much CRAP around the EGR on a 93 LT1, will have to take it to someone to change it.

In the meantime...

Took off TB, cleaned out the TB & IAC valve, new gaskets, torqued everything down(there were a few loose bolts on the TB/IAC assmbly), took it for a ride, and BOY that REALLY helped big time

AND , still hesitation between 1000-2000rpm, and also slight misfire at idle...

EGR...It's got to be...

What I can say is that, through my experience for the past few months, everything that I did replace or clean out DID help, some more so than others, and yet, I still have to change my EGR...

I figure, hey, my car is running better, so everything that was changed has helped, it's been worth it.

Anyway, that's about it...

Any comments?

 

if it works let us know =O there are many of us trying to get rid of this damned problem =/

 

I assume you arent setting a SES light? If it were the EGR(Exhaust Gas Recirculation) or the cat's you would be most likely setting this light since it is controlled by the emiisions crap on the car. What kind of gas are you using? What kind of mods? Sometimes the knock sensor on these cars will sense false knock and advance the timing. are you running rich lean don't know?

Just trying to help out and get this problem fixed.

 

Wouldnt it RETARD the timing?

 

That is REALY funny. I have the SAME problem, and replaced all the same things, and YES they all did HELP ALOT! BUT the problem is still there, my car is not getting an SES light, and is not throwing any codes, and according to snap on computer, the pcm is sending a signal to the egr but there is no way to see if it works. It could be sticking, anyone have a pic of where the egr is on a 94 t/a?

 

The EGR is here .

 

Thanks Shoebox. Question, what would be symptoms of a faulty egr or a sticking egr? I dont have an ses light or any codes. Could this still be the issue?

 

So what's your thoughts on this shoebox? My car has not ever thrown a code, xcept for when the ICM died, THEN it threw a code when the Chevy dealer scoped it, other than that, it hasn't thrown a code since. This was over 70,000 miles ago.

Symptoms are, slight hesitation btwn 1000-2000rpm, but only when the engine's warm, also misfiring at idle, erratic idle at times. Cleaning out the TB helped tremendously, and, still same stuff. Everything else has been changed...

 

An EGR that is sticking open can cause poor/rough idle, stalling, surging during cruise.

It's not hard to get off, once you get to it. Removing the EGR solenoid gives a little more room to get in there to it. Use of a mirror can help, too.

 

Thank you shoebox, I kind of remembered what a "sticky" EGR does. I'm going to have to change that thing sometime soon.

 

My car had the symptoms shoebox described and kinda had a hesitation between 1k and 2k, replaced the EGR (new one, not cleanedout) and it has run better, but sometimes i feel it surge just the TINIEST bit. I think it is because i hit the throttle and give it like .001% opened on the TPS though, so that it wont pick up that i opened the throttle and it kinda feels like a vacuum leak? Maybe you should try cleaning the mass airflow sensor?

 

93's don't have MAF sensors

Thanks for the thought though

 

When my EGR was bad it did not set a code, it just started surging at low rpms. I thought it was opti at first, but it ran good at high rpms, so I figured I'd try the cheaper option first and it fixed it.

 

Hi Carlos, I have 93 z and I just changed my EGR valve. On the 93 f bodys the fuel lines are in the way of the EGR valve. First disconnect the the battery and relieve the fuel pressure. What I did I took the 4 bolts that hold the fuel rail out, then I pulled all the injectors out, make sure that you disconnect the electrical connectors and label them so you know where they go back on. Then remove a bolt that holds down the fuel lines its by the intake on drivers side, this will allow you to move the fuel rail more then all I did is I lifted the and pulled the fuel rail out of the way it was sitting on the top of the intake. From there I was able to get to one of the bolts on drivers side the other bolt I got the from the passenger side you have to feel your way to it. You have to remove the old gasket that is going to be tricky because there is not much room. Use a mirror to see how are you doing back there. Then install a new gasket and EGR valve and put everything back together.

 

mine throws the ses off and on all day so im starting not to pay it any attention anymore. but , if i was to seafoam the car really good would that get alot of the carbon deposits and stuff out of the way thats causing the egr valve to stick open in the first place? i know it would prolly still stick sometimes, but maybe not as much ?