weird problem
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weird problem
Alright its been like -20 degrees here in Iowa for the past week and Ive been having problems with my truck. Its a 1988 f150 4x4 5sp 300 and when it gets to operating temp while just cruzing holding less than half throttle it starts sputtering like its loosing power. If I push more than half throttle it goes away. It doesn't matter if its in 1,2,3,4,or 5th if im pushing less than half throttle it bogs. As soon as I push the gas it goes away? I replaced: plugs, plug wires, ignition module, coil, fuel filter, checked iacv, tried unhooking the egr by plugging the vac line. Im stumped and this is my daily driver. Ill be doing a compression check tomorrow and also checking the vac lines. any suggestions? Its never done this except when its really cold out. Oh and it idles fine and revs fine.
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Joined: Jun 2009
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From: Hudson,Michigan
Just pulling straws,but after you have checked all the cheap fixes,maybe a throttle position sensor? They are probably not cheap,but they do tell your computer where the throttle plates are.There is probably some resistance checks that could be done but you would have to check the manual,or maybe someone on here could help.I'm not very good at this electronic stuff.
Logistics Pro
Joined: Nov 2009
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From: Lawrence Swamp
an '88 has OBDII or whatever that diagnostic thing is? I'd check the linkage/cable from the skinny peddle, cold may = choke, rpm may = ignition? but don't ask me 2 much, aint a mechanic.
Good luck, check back in if still troubles,
Good luck, check back in if still troubles,
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It sounds like it could be an oxygen sensor. The computer doesn't use oxygen sensor feedback when the engine is cold, or at heavy acceleration. Just warm cruise, to try to keep the air/fuel ratio at 14.7:1 for lowest emissions. If the sensor is bad, the computer could be overcompensating for a false AFR reading during warm cruise, causing a sputter. As far as I am aware, all other EFI sensors are used all the time.
Pre '96 EFI uses OBD 1. You can pull codes by grounding the STI pin of the test connector under the hood, and turn the key on. It will flash error codes through the check engine light. There are many writeups around on how to do this, and it only costs 1 piece of wire. Personally, I think it's a pain in the a$$, so I just got a code scanner that can handle obd 1 codes.
Pre '96 EFI uses OBD 1. You can pull codes by grounding the STI pin of the test connector under the hood, and turn the key on. It will flash error codes through the check engine light. There are many writeups around on how to do this, and it only costs 1 piece of wire. Personally, I think it's a pain in the a$$, so I just got a code scanner that can handle obd 1 codes.
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Just did a compression test on the truck it was from the the front to the back 140,140,150,120,150. The truck has 189,000 miles. I put oil in the chambers and it changed the numbers a small amount. I am going to run the self test for codes and post them up
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Alright its been like -20 degrees here in Iowa for the past week and Ive been having problems with my truck. Its a 1988 f150 4x4 5sp 300 and when it gets to operating temp while just cruzing holding less than half throttle it starts sputtering like its loosing power. If I push more than half throttle it goes away. It doesn't matter if its in 1,2,3,4,or 5th if im pushing less than half throttle it bogs. As soon as I push the gas it goes away? I replaced: plugs, plug wires, ignition module, coil, fuel filter, checked iacv, tried unhooking the egr by plugging the vac line. Im stumped and this is my daily driver. Ill be doing a compression check tomorrow and also checking the vac lines. any suggestions? Its never done this except when its really cold out. Oh and it idles fine and revs fine.
probably a coolant temp sensor......thats what id be looking at first
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I figured out what it was. It was a corroded wire that cam off the negative terminal on the battery that connects to two different wires it was barely connected. I had trouble with it before...
runs like a rapped ape now!
runs like a rapped ape now!
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