Shutting down while driving after much work PLEASE AND THANK YOU

eric 87

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Emergency. If I can't figure this out I will let shop have one more crack at it. Then I will put a ford engine in it just to spite the truck!
Here is the issue. I had a missing engine when I had to accelerate and it got worse. Like a pack of lady finger firecrackers going off. It is a 87 stock 305 TBI.
Replaced and also TESTED each sensor with appropriate tools.
TPS, Map, IAC and Temp sensor. None of it worked.
Rebuilt the Throttle body and replaced the computer using the Prom chip in the old computer. Didn't totally fix issue but helped it a bit
Took to the shop to have him go over what was done. This fellow and his shop know GM products....well most if not all products but they race GM cars as well.
He replaced the distributor. The pickup coil was shot the magnets were off etc. He also checked the throttle body again and pressure.
AH at last it was fixed.....but wait. The drive home...it seemed to cough as in nose dive and then take off and that was at a steady speed maybe light accel.
As I continued home with wife following me in my old farm truck (FORD) it did this more often randomly. As we neared home it was pronounced as if the truck was being shut off with the key or as if I was totally out of gas. Had half tank. I drove to the neighborhood gas station with flashers on since I was on back road. Nope I was half tank.
When I restarted it the RPMs went HIGH. Shut off and restarted and they went LOW barely idling. Next day wife thought she would attempt to drive it to grocery since it otherwise had driven great on the way home.
It quit on her a mile from home at stop sign. Idle was so low. She had no steering and got it to a driveway and restarted it to have it rev probably over 2500 rpm. She turned around and brought it home and took old betsy the farm truck.
I drove it later about 10 mile circle and NOTHING HAPPENED until right before getting home. It did a quick cough again as if a split second power off. No backfire.
Next morning I called shop and he was going to go back through everything that had been done. He had it on a laptop doing the tune and took it out and it never acted up before we picked it up. But he said he would rather I be happy than to lose business.

I left to take back to shop and this time it shut down a mile from home. Driving steady speed. About 40mph. First the engine off but the radio stayed on. But then all of a sudden I lost the radio. Coasted to a driveway. While coasting I put in neutral and tried to start it. Nothing. I got to a driveway put in park and cranked....nothing. Then doing what you are not supposed to do....I pumped the THROTTLE BODY a few times and it started. IT of course ran rough initially but only a few seconds and it smoothed out. I took it home though since she was at work and could not follow me the 20 miles to the shop. IT is going back next week by driving or by rollback.
If someone can help me in a direction to search I would appreciate. If I or he can't find it I will either do a carb swap and ditch the TBI OR SELL IT AS IS and let the person know as it might quit on a test drive. SO far this has cost about 550 from the parts and labor gun. Much of it done myself. I may toss all the new stuff and do the intake carb distributor etc. Cut my losses.
I like it but I do not like being on the side of the road.

I love my classics as my other is a 69 firebird. But I will not keep what I can't drive. My 69 is local show quality but I drive and do not have historic tags on it. If it doesn't get driven it gets sold.
So Pleading for help as I rather like this truck. But when a round nosed ford with 276k miles is more dependable...

Sorry to be long winded. But an update. It also dropped voltage when I hit the brake pedal. Down to 8 on the gauge! I tested the alternator and battery. I turned every accessory on I could and tested as well. Alt checks out. But could it be going bad and it cause the power failure randomly?

Even though it started with the pumping of throttle body I think this is electrical. That had been rebuilt and it wouldn't explain why I am losing all power even to radio with key still in the run position.
 
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OldBlueDually

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This sounds a LOT like my 96 Suburban 1 Ton 454 (yes, 1 ton, not a typical 3/4.....it was a special order for the Fire Department ;) )...anyhow I digressed there!

My suburban would do that too, never left me stranded but scared the he!! out of a guy when pulling out into traffic and "poof" all power off including engine, then "poof" all back on. My volt meter gauge would also read 8 to 10, and would sometimes jump up to 14'ish.....

One day in my shop, I opened the drivers door to jump in, interior lights & all are on, then I hit the key and all went dead to the world. Nothing worked, lights, radio...etc.

HERE was this particular problem: A splice in my battery cable was going bad!!! The cable went from one side of truck, to the other and was spliced halfway through. Between this, and a ground issue I had these power issues.

I sold it to my dad (a 35 year GM mechanic, now retired) as I bought a beautiful '01 3/4 ton suburban. He went through the wiring a bit better and replaced the faulty wire (I had re-crimped it at the local semi truck shop), he also found a couple ground issues with it. Since he has had his hands on it, that volt meter runs 14 and has NEVER had that issue again.

Not sure if any of the above is useful, but I really hope you can get it figured out!!
 

dvdswan

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Fuel pump breaking down or the ground to the fuel pump.
 

Termite_Delight

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It sounds like an electrical problem to me, check your grounds and fusible link at the starter.
 

eric 87

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DVDswan we checked all the fuel and pressure and rebuilt the throttle body and pressure regulator. I will say this shut down killed all power. And when I hit my brake pedal once back in the drive way I noticed it took the amp gauge down to 8. Nearly bottoming out. When I let off it came back up some and then slowly got to normal. Hit the brakes again and down it went. Before the missing issue I would nervously watch the amp gauge as it went down often. But when I put a load on the battery it still checked out as did the alternator with the meter.
This has me stumped. Distributor had a bad pickup coil. One other thing I have had to use just the drivers tank since I bought it 10 months ago. If I flip the switch and then turn on the key the right fuel pump primes but it will not start. IF I have it running on the drivers tank and flip it while running it completely kills the engine instantly. Since I hear the right side prime I am thinking the pump and the circuits may be good but someone said there is a hose inside the tank that often deteriorates and loses lift or something. I have no idea. It has me thinking tbi to carb swap move tank to a single rear with electric fuel pump. If it runs good I keep if it doesn't I sell and cut bait.
Thing is the engine bottom end and top end are in good shape. When it isn't dying now it runs the best it ever has since I have owned it. The 305's have never had power but it is night and day with the new parts and the new distributor. I wondered if there is a big ground wire or a hot to distributor or something so I will be under hood tomorrow. If no one has a clue it will go back to shop next week and it will determine what I do. I want a nice truck. And it is nice. The mechanic thinks I need to hang in there since it is so nice otherwise. But I have a really nice driver 69 firebird I prefer to spend the money on if I am spending money. But I do like my truck so....I am hoping. I will check the fuel once again and get under it and over it looking at all grounds. Not sure I know where they all are but will look all over.
 

eric 87

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OLD BLUE DUALLY. Appreciate the help. I will be taking everyones suggestions and looking. At this point....Not sure if you saw this but FORD has now offered the new electric motor they are using in the MachE as a crate motor. Sold out at sema.
I would hate to be vulgar and put a ford engine in the thing. Naw can't do that I would sell it first lol

Termite...thanks. I will check grounds in the am. Unless I wake in the middle of the night. I will have to turn on heat though as it is getting in the 20's tonight. Rolling around on a creeper at 3 am.

I am really thinking the way it is doing this it has to be a power issue. But the weird thing is that when I pulled off the road it would crank and not start. Then I pumped the throttle body (NO NO I KNOW) and it fired up! But I think that was just an oddity UNLESS the ground back there somewhere. But would it shut the entire truck down including the stereo?
 
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OldBlueDually

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OLD BLUE DUALLY. Appreciate the help. I will be taking everyones suggestions and looking. At this point....Not sure if you saw this but FORD has now offered the new electric motor they are using in the MachE as a crate motor. Sold out at sema.
I would hate to be vulgar and put a ford engine in the thing. Naw can't do that I would sell it first lol

Termite...thanks. I will check grounds in the am. Unless I wake in the middle of the night. I will have to turn on heat though as it is getting in the 20's tonight. Rolling around on a creeper at 3 am.

I am really thinking the way it is doing this it has to be a power issue. But the weird thing is that when I pulled off the road it would crank and not start. Then I pumped the throttle body (NO NO I KNOW) and it fired up! But I think that was just an oddity UNLESS the ground back there somewhere. But would it shut the entire truck down including the stereo?

A total power loss would also kill the radio. Not sure how the radios are wired for power (through ignition or other???), but I am wondering if it is powered through the ignition switch, would the switch cause any issues like this that it kills power to everything..??
 

OldBlueDually

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Also, to get someones attention on here too as an FYI is to put an @ symbol and start typing their name....like @eric 87 now you have a notice I mentioned you in this post ;)
 

eric 87

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Engine Size
305 tbi
Thanks @ Oldbluedually
 

mtbadbob

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Also, maybe swap out the battery, I have seen them short out internally and cause weird issues.
 

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