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<SOLVED> New head now runs like crap


Brandoncw

Active Member
Joined
Mar 7, 2016
Messages
27
Transmission
Automatic
EDIT: This is a 1999 ranger non flex-fuel 3.0

So I had a cylinder 5 and 6 misfire. Narrowed it down to bad valves. After I replaced the head it no longer will idle right. It idles rough at about 400 rpm, sometimes it kinda lopes. If it does idle right, as soon as you put any load on the engine it falls flat on it face and stumbles. I put new injectors, lifters, and pushrods in it while I had it apart. New MAF sensor the week before. I checked over every electrical and vacuum connection I could find and no luck. I found its kinda drivable with the MAF unplugged. If I unplug the IAC sometimes it stalls, sometimes it starts idling perfect. I'm stumped, any help is appreciated

I checked voltage at IAC, said 12 volts KOEO, also checked IAC resistance. It came out at 9 ohms. Truck ran perfect aside from misfires at idle before the head replacement
 
First guess, you have the spark plug wires wrong

You have the drivers side in the wrong order
Capture.JPG
 
First guess, you have the spark plug wires wrong

You have the drivers side in the wrong order
View attachment 87264
I checked that multiple times, it's what I thought too.

If I mess with unplugging sensors and get it idling right, it idles smoother and better than it ever has before since I've owned it too. Smooth, no odd sounds from tail pipe, and no longer sucks a dollar bill up the tail pipe like it did before
 
Last edited:
Decided to cross reference my old injectors with my new ones. Truck has Vin code "U" so non flex fuel... well the old injectors cross referenced to 21.1 lb/hr injectors... meaning flex injectors. Put them back in and she purrs like a kitten. Dunno why the heck someone would go through the trouble of swapping in a flex, sure wouldn't be me
 
Glad you got it back to running.
 
Glad you got it back to running.
Still has a very slight tremor/stumble at an idle. The D/S head had real bad exhaust valve recession causing a loud tick and cylinder 5 & 6 misfires. I'm sure the P/S side head isn't in much better shape so when I get the time and funds I'm gonna replace it too. Get the right injectors while I'm in it again as well

P.s. Thanks for your service 😁
 
Any idea why it would run better with the incorrect FI's?
 

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