96 2.3 codes p0300, p0171

[Mike Daley]

first off let me say that i am new to the forums here. so anyways, my ranger has a miss fire at idle, sputters at low RPM's and sometimes will idle so rough that it will stall. the codes i got from the CEL were p0300, and p0171. i changed the coil packs, and cleaned the maf sensor. i also checked vac lines and intake manifold gaskets for leaks but i didn't find any. i do have a 97 2.3 ranger parts truck sitting in my yard that did run mint so i can rob sensors from that if need be. thanks in advance!

 

[Mike Daley]

i would also like to add that i am only hand calculating 20.1 mpg. when the 97 was on the road, it was getting 30mpg with a bad rear end

 

[adsm08]

This is a tough one to do without seeing the truck first hand. Your codes are circular. A lean condition could cause your issue, but misfires on all cylinders (your random misfire code) can cause the computer to see a lean condition that doesn't actually exist.

Check fuel pressure, if it is in spec, then unplug the MAF and see if it runs better. If so swap the one from your parts truck. If the problem is still there look for air leaks. That's where I would start from.

 

[Mike Daley]

This is a tough one to do without seeing the truck first hand. Your codes are circular. A lean condition could cause your issue, but misfires on all cylinders (your random misfire code) can cause the computer to see a lean condition that doesn't actually exist.

Check fuel pressure, if it is in spec, then unplug the MAF and see if it runs better. If so swap the one from your parts truck. If the problem is still there look for air leaks. That's where I would start from.

yeah for some reason i kinda had a feeling that this will be a tricky issue to solve... i already checked for air leaks and couldn't find anything. but that doesn't mean that i didn't miss anything, so i will check again. if i remember correct, when i would unplug the MAF, it would idle smooth but a little high at first, and then after about maybe 20 sec it would drop down to a super low and shaky / loping idle. i will unplug the MAF and check for air leaks tomorrow after work and report the results back here tomorrow afternoon. thanks!

 

[ranger1997]

Check for a vac leak between the upper and lower section of the intake where the evap can vac line connects to a metal line and down towards the evap can. Had this and was hard to find until I sprayed brake cleaner in there and had a rpm change. Check your pvc valve also, could be loose down in the hole.

171 lean bank one and 300 random miss fire.


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