who did the motor install? was it a complete long block or did you assemble the engine itself. sounds like either the timing is off, which should have been checked right when motor was put together and fired up. Might have a fuel pressure issue also. double check your plug wiring routing and that your running the proper firing order.

are you running just an msd coil or did you install the entire msd box as well?

 

Thanks for your reply
I purchased a complete long block and assembled it from there. I had a good friend of mine with 30+ years experience do the timing for me while he was around and i was at work. At first i had the timing 180* out when i assembled it.. it was firing on exhaust and i couldn't work on it anymore from that point on for about 3 weeks due to work. So he did it for me. But i will double check. I wish it were just off enough do cause the issue so i dont have to mess with everything else. I took my truck off the road in april when my inspection ran up to do this entire front end work. and because of my crazy work schedule i am just finishing it up now :banghead. Still have to put the grille and bumper/grille guard on haha

Thanks
Tim

 

First thing you should do is scan for any trouble codes and go from there. My Bronco had similar symptoms and turned out to be my TPS went bad, but your results may very. Scan codes before you start throwing parts at it.

 

I don't mean to thread jack but will it still throw codes if my check engine light is not on? 89 5.0 btw, I'm having sputtering underload once its all warmed up all of a sudden.

 

have you put a vacuum gauge on it?

I'm going through something similar and i finally bought a 25 dollar kit and realized i only have 10 inches at idle. and from my readings, i understand that could be caused by an intake vacuum leak or late valve timing but this motor ran fine in the previous vehicle it was in and i switched out the intakes so i could run fuel injection, so I'm going to go with the intake vacuum leak right now and check that first .

Good luck

 

to answer your question vanilla, yea you can still have codes stored if you don't have a CEL

 

Ok thank you very much

 

Double check those vacuum hose connections for leaks and check that they are all connected to the proper port. Good Luck opc1:

 

88 351 sputters backfires like its out of gas

right now im having a problem with my 88 5.8 4" lifted 33x12.5 4.10ls. it keeps sputtering like im running out of gas. my check engine light flashes while its sputtering then goes back off. then motor goes back to normal. maybe a few mins later will do same thing.. not sure if possibly injectors, fuel pump/filter, wiring, or ?. going out to do some nosing around right now. since check engine light is not on normally dont think i can pull any codes.. any info would help. have been driving it around with this problem but dont need to get stranded somewhere because i didnt give it the attention it deserved. thanks

 

right now im having a problem with my 88 5.8 4" lifted 33x12.5 4.10ls. it keeps sputtering like im running out of gas. my check engine light flashes while its sputtering then goes back off. then motor goes back to normal. maybe a few mins later will do same thing.. not sure if possibly injectors, fuel pump/filter, wiring, or ?. going out to do some nosing around right now. since check engine light is not on normally dont think i can pull any codes.. any info would help. have been driving it around with this problem but dont need to get stranded somewhere because i didnt give it the attention it deserved. thanks

You can pull codes without a CEL, and there is a good chance you have some stored. visit http://oldfuelinjection.com/?p=13 and read up.

There's about a million things that can cause what you're describing, so we'll need to spend some time narrowing it down. When did it start?

You'll want to verify the basics, do you have proper fuel pressure, etc?

Do you have proper airflow?

What condition are your plugs / wires and general ignition system in?

 

Check everything mentioned above. Also, check and make sure the TPS sensor is adjusted to the correct readings.