Well about 3 months ago my rig coasted to a stop on the side of the road. initially I suspected a fuel issue however I found it to be electronic. I have changed the coil, ICM (twice), distributor (twice), have cut my wiring harnes open and inspected the wires for breaks, shorts, grounds, etc, etc..... I also installed an intake air temp sensor (ACT). When I pull my engine codes I get 21, 24, 31, 67.. Since I changed the ACT, one of these codes should be clear (either 21 or 24) (the other is ECT) 31 has to do with EGR, EVP so I am going to look into that. 67 deals with neutral switch and other possible status lite codes. What happens is it starts good and runs well for about 10 minutes. Once it warms up, it will cut out causing a loss of power , caughing, hic-ups and bucks. I have to limp back to the driveway and let it cool down. That's if I make it there before it shuts down completely. Once ot cools off it will run again. If I rev it up to about 3000 rpm. I can watch it cut out Intermittently causing the rpms to drop by 1000, it will do that for a minute or so (all the while getting worse) untill it shuts down. I am confused beyond confused. Could it be the PCM????????? Something is failing when it gets warm???????? I miss my old Chevy at this point. Thank God for good smoke and patience. But i'm running out of both lol. Possibly a collapsed lifter??????? I'm running 20-50 wt with Lucas oil treatment. I bought a throttle positioning sensor but I am not getting any codes for that. Cmon you gear-heads. Shead some light for me. I'm lost................

 

OK 24 hrs and no reply....I failed to mention that my rig is an 89 F250 with a 5.8 (351) injected.

 

Codes 21 and 24 can be triggered if you did not warm up the engine before running the KOEO tests. You never did state what tests you were running and when the codes were displayed, i.e. Key On Engine Off (KOEO), from Continuous Memory (CM), or during the Key On Engine Running (KOER) which should not be checked until you can pass the KOEO/CM tests.

Code 31 indicates the closed EGR signal value is below 0.24 VDC (KOEO/KOER) or the value has intermittently failed in the past (CM).

Code 67 has several definitions depending on when it was displayed. KOEO/CM indicates a problem with the Neutral Safety Switch circuit. KOER indicates the PCM thinks the A/C is on during the test. If you have a manual transmission and the 4.9L I6 engine then you need to keep the clutch engaged during the tests, otherwise you will get this code.

You need to determine if you are losing fuel or spark when the problem occurs. A small investment in tools, fuel pressure tester/spark tester/DVM, would eliminate a lot of parts swapping and guesswork.

 

My 96 F250 died when stopping, but it turned out to be the speedometer head. I don't think you have the same type of speedo though.

 

Hey rla2005, Thanks for the input. I picked up a fuel pressure tester today and made up a set of jumpers to keep my voltage tester in the cab with me. I'll see what the next round under the hood brings......