i've had advanced auto check my obd for free (the plug outlet is to the right of the gear shift in the cab of my '96) and it's said the engine is running too lean. given the way it acts, like it's choking out, that makes sense. also, sometimes the starter will not work well/jam up. i'm pretty sure it's the original part though and may not be related to the fuel issue. where are the temp sensors? i've had mine give me problems in cold and hot weather, but it does happen more often when the engine itself is warm.

 

I bought a fuel pressure tester yesterday. Life's been too busy since I first posted. It was about 84 yesterday so I thought it would be a good day to test it out. The pressure is holding right at 40 psi while its running. When I accelerate it drops down to 35 psi. With the key on engine off, the pressure did not move past 40 psi. When I disconnect the vacuum line from the pressure regulator the fuel pressure did no move. There us good vacuum going to the regulator. After reading the Hayes manual at the parts store the pressure should have gone up between 5-10 pounds. I forgot to squeeze off the return line to eliminate the regulator being at fault. Is it possible the fuel pump isn't producing more then 40 psi so the regulator can't do its job? Its going to be in the mid 80's today so I'll check it out today again.

Thanks,
Kevin C

 

It's not the engine temp that matters causing the fuel issues,it's the pump running in the tank that starts to get hot and thats probly when the pressure starts to drop,if you can keep your pressure gauge hooked up and tape it to your windshield while driving you can see if the pressure drops when the problem starts,that is how i do it when the pressure gauge wont show a bad pump without driving it and being under a load and the pump is running under temprature.If you cant see the the gauge when driving then at least have someone put it in gear with the engine running and powerbrake it up to about 1800 - 2000 rpms and see if the pressure starts to drop,with the engine under a load.

 

I know this sounds silly, have you checked the gas cap? It's possible that the gas cap isn't venting, etc.

 

Yesterday afternoon it was about 80. I hooked up the gage and sure enough, it was acting exactly the same way. No more than 40 psi and when I hit the gas it dropped below 35 psi. I left the gage hooked up and waited until dusk. By then it was in the low 60's. Started up and the pressure was a 45 psi. I hit the gas and the pressure went up to 50. I disconnected the regulator and it went up to about 60. This shows me the regulator is doing its job, but the pump isn't doing its job while the gas in the tank is hot. I'm placing an order for a new pump today. Thanks for your help.

Kevin C

 

Did the new pump fix the problem? I'm having the exact same symptoms.