The first time this issue showed up was 4 days after racing at Orlando Dragway. The car run great and I decided to continue to drive the car to work Thursday and Friday, then on Saturday, the issue showed up for the first time. The engine seems to loose power and then suddenly pickup again, causing the car to buck back and forth.

This occurred about 4 times in 15 miniute period while driving on the xway at 70mph. Not knowing what it could be at the time and having no place to work on the car, I put it back in storage. 6 weeks later, I am all moved into Florida with garage and tools. I check under the hood and find the negative battery terminal a smidgion loose. I tighten it up, and go for a drive. No problem, car and engine runs great.

So, I take the car back to the dragstrip. I make one run in 3 hours and decide to head home; car and engine runs fine. I park the car. One week later, I take the car out for a weekend romp. About 3 miles from home the issue appears again. This time much more violent. I take the first exit. Pop the tranny into neutral and try to keep the engine from slalling all together. Its a very long red light (of course). The engine is surging up and down. I make back home,,, dont know how. The engine dies in the garage, what luck. And the engine will not restart. I had a scanner ready to go on this trip, the error code is 45 --- rich O2 sensor.

Today I replaced the fuel filter and the O2 sensor,,, items that need to be replaced anyway, it was time. And I erase the error code. The engine will not start. Sounds like it is firing only on 3, 4 or 5 cylinders. I then removed the valve covers to check the valve train,,, all is good.

So now I am thinking the coil or dizzy. The fuel system holds fuel pressure for one hour till it is zero. I have a fuel pressure gauge hooked up all the time in the engine bay. Any ideas from anyone?

 

My car had a problem similar to yours, turned out to be the Ignition module.

The TPI board could help you as well.

 

Are you referring to the electronic module inside the distributor?

 

Yea, you can have it tested but be sure to get it warm. try sitting yours on the defroster vent on the way to the parts store. Have them test it three or four times. This will warm it up even more. I took mine off while it was still an intermittent problem and had mine tested (1 time) and it showed good. So I put it some more dielectric grease on it, put it back in and kept searching. It would still happen rarely when all of a sudden it wouldn't start one day.

 

Thank you for the help.

 

I took the electronic module into Autozone,,, the tech guy tested the unit 10 times,,, it got plenty hot. The unit tested good all 10 times. Now what?

 

Apparently, the ignition is up to the task.

Is the fuel pressure normal and holding on shutdown?

I'm thinking about the leaking or streaming/puddling injector possibility, or FPR diaphragm possibility. I beat my head against the wall with a similar bout about 8-10 years ago. Turns out the freshly cleaned injectors (Motor-Vac) were not cleaned at all. Cruizin' fixed that for me.

Are the plugs now fuel fouled from running rich? That could be the no-start, at least.

 

I'm having a similar problem with an LB9, but it is no longer intermittent, just a horrible midrange and very rich idle. Between myself and the previous owner, we've swapped out virtually all of the ignition and sensors, and it still runs like poo. The only thing left is the injectors.

 

Had the same problem on LB9. My distributor was plain worn out, Would act up when hot. All of the springs and weights were worn out. Very intermitent. Replaced w/ MSD pro billet and never ran better. Replaced two modules before I figured it out. I have the MSD distributor w/ about 10K on it. sitting in the garage $150 BUYS IT IF YOU NEED??
I would pull or open up dist. check for any kind of white or yellowish powder. If so that is the pickup coil worn out, had that problem too.....

 

I also replaced the entire distributor with no positive effect apart from my wallets' lighter weight allowing the wheezing, coughing car to accellerate quicker.

A quick check for bad injectors is to pull the plugs off and check for 13-17 ohms. Anything open or too high is a bad injector.

TA

 

here is an update:
1) I purchased an ignition module (the thing that screws down inside the dizzy). Started the engine, the engine ran but was not firing on all 8.
2) Bought new AC Delco RapidFire plugs. Installed them, engine would not fire up at all. With my busted-up knuckles, I decided to quit for the nite.
3) I check on here, I see some responses, thanks for the help.
4) I got inspired (seeing the responses), went back out to the garage just now to check if the injectors are getting a signal by using a niod lite. Sure enough, at least #1 is.
5) So I try to start it again. The engine turns over big time with my new high torque starter. The engine will not fire up. So I give it some gas pedal, the engine starts up, but runs real bad. The engine runs so bad, that it seems like it wants to come apart.
6) I did check 4 of the injectors (the 4 that I can get to). They all measure 14.5 Ohms.

Vader: the fuel pressure stays up for about 1 1/2 hours after key off.

So, what would cause an EFI engine to need gas pedal to get enough fuel? Bad MAF? Bad TPS?

 

Vader: the fuel pressure is not staying up,,, it drops as I watch it now. 50psi is lost in 15 minutes. The injectors are about 10 to 12 years old. Also, the Holley AFPR is 7-8 years old.

BTW: the old plugs (2-3 years) are blackkkkkk,,, lots of soot.

 

If they're all black and sooty, this would point to a very rich mixture, so it's safe to assume all injectors were firing before the new ignition module. First, re-install the old module and see if the engine resumes it's momentary proper idle. Also, are you saying your fuel pressure drops from 50-psi to 0 after your shut the engine off? If so, look into your gas cap, as this sadly gets overlooked at times. I wouldn't even suggest a bad TPS or MAF until you put the old moduel back in, as you might have bought a new one from a bad batch (it happens)....

 

More detail on fuel pressure: As I watch the fuel pressure gauge that is mounted in the engine bay, I can see the fuel pressure increment down in 1 psi increments, it looks like a second hand on the clock, clicks down 1 psi every 2 seconds, until it reaches 20 psi, then it holds a bit, but still slowly bleeds off to 0 psi in a total of 15 minutes.

So I have that issue, which might be the fuel pressure regulator, or a bad injector.

But, what would cause me to give the engine some throotle to get it to fire up?

 

...same as me, too much fuel (leaking injector(s), not enough air.

TA

 

Are you maf? If so, did you unplug the maf and try to start it?

When was the last time(or ever) have you replaced the pickup coil(under the ignition module in the distributor)?

Have you verified that the tps sensor is getting voltage and is sweeping as you open the throttle?

 

I am running the factory setup for remote coil and small cap dizzy. The remote coil is 12 years old at least. I think that coils either work or dont at all. I dont think that the coil would lead to an intermittent problem or missing cylinder fires.

I just checked the TPS one minute ago. It is functioning just fine.

So, I am leaning toward a bad injector. Well, they are maybe 11 to 12 years old. I got my moneys worth out of them.

But, here is my delimma. In order to change the injectors, I have to remove the SR. I promised myself, the last time that I put it on, that that was the last time. I told myself that I should get an HSR!!! I just dont want to spend the money now. But, anyway, here is my excuse to upgrade to 30# injecors and an HSR.

 

I know where you're coming from. If you must, I suggest getting intoxicated first and have a friend over to hang out and distract you/cheerlead.
It may lower the anxiety.

 

Do you know a good looking female blond who can help out?