Nothing last for long

[rjm1998]

I have a 1998 Chevy k1500 5.7 vortex 4x4.

 

We put a new motor in 13 months ago. Ran great for about 6-8 weeks. The truck has had multiple problems come and go: difficulty starting, dies after cranking, jerking, surging, won’t crank and only spins, backfires, rough idle, missing, bad gas mileage, dies while driving (newest problem). 

 

So so far we have replaced: spark plugs, plug wires, coil, crank sensor, thermostat, MAF, PCV, fuel regulator relay, spider with new fuel pressure regulator, fuel pump, fuel filter, distributor x 2, cap x3, button x2, temperature control switch, added a ground then removed...I feel like I may be missing something else.

 

Valve cover has been removed and were found to be working fine. Compression test was good. Fuel pressure test is at 59. 

 

It gives random codes for distributor, fuel injector 1 malfunction, bank 1 misfire, cylinder 3 malfunction, and the list goes on.

 

We are at a loss on what to do, and can’t keep throwing money at it. It seems like when we replace one thing it will run great for a minute or a couple weeks, then starts same thing over or comes up with a new problem.

[Bigfutz]

ECM? Have you hooked it up to a data logger? Sounds like you need a proper diagnosis before throwing more parts at it. Who changed the motor and why?

[rjm1998]

No, we haven’t hooked it up to a data logger. We started with the basic tune up things, and then changed some things related to codes pulled from the part store code reader. The motor was changed a year ago raise the old one was knocking and blowing smoke.

[Brian Lindsey]

a code reader from auto parts store is not that accurate ,it doesn't dive deep into your system , you need a high dollar diagnostic reader , that will show you more than a number, for example; did you reset crank and cam sensor , they have to be recalibrated  , and synced when changed, these are computer controlled engines , you have to match up everything to computer so it can read it and adjust the parameters accordingly. it may be better if you take it to a driveability specialist

[Mikebtte]

Have you checked to see if a spark plug wire is grounding on something. I have had cheap wire arc off the wires to a manifold or other metal item and throw off the ignition system.

[rjm1998]

No, we haven’t hooked it up to a data logger. We started with the basic tune up things, and then changed some things related to codes pulled from the part store code reader. The motor was changed a year ago raise the old one was knocking and blowing smoke.

[rjm1998]

We have looked for the plugs/wires arcing and there is nothing. We have new AC Delco wires on the truck.

[east3021]

I’d start with taking care of the codes. GM published diagnostic tables for each trouble code (DTC) that gave the technicians step-by-step procedures for remedying each code. These are available in the factory service manuals here...

http://67-72chevytrucks.com/vboard/showthread.php?t=700011

...or at online subscription based services such as alldatadiy.com. Since it’s a bit easier to navigate and is pretty close to the factory manual, I’d get a subscription (it’s around $30/year) and go through each code’s diagnostic procedure to see what the issue is.

Good luck, I hope this helps.




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