'90 Ranger Bad miss/surge

[FordFreek!]

My '90 Ranger is experiencing a pretty bad misfire after doing a tune-up. I changed the plugs (gapped to .045), wires, distibutor cap, rotor button, air filter, fuel filter, and cleaned the IAC. It had a barely noticeable miss before the tune up, that's why I did it. Now, it's pretty horrible.

At idle, it's definitely noticeable, and at cruising speeds (RPM's below 3K) it bucks and surges. The weird part about it is WOT runs are as smooth and (somewhat) powerful as ever! At idle in neutral it will revv up just fine without any hesitation as well.

First thing I did was check the firing order, again and again. Made sure all my wires were properly seated on the plugs and on the distributor prongs. Pulled the plugs back out, they were all clean and properly gapped. I pulled the wires off one by one to try to isolate the misfire, but every plug wire I removed made around the same impact on the motor.

Next I ran codes. KOEO, I got code 95 - fuel pump secondary circuit failure. Don't know what to do about this. Fuel pumps comes on at the turn of the key, relay clicks... KOER, I got 11 (pass code), so nothing there.

Then I hooked a fuel pressure gauge to the schrader valve on the fuel rail, and at idle pressure was a steady 35 PSI. I also removed the vac. line to the FPR while running to see if gas came out. I checked for vac. leaks as well. I hooked up a vac. gauge and I'm getting around 18-19 Hg at the manifold.

Now I'm outta ideas, not sure what to check now. I've checked everything I know to check, but nothing helps.... Any ideas?

 

[shane96ranger]

Does the motor shake really bad? Years ago I did a tune up on my buddies 2.9 and had some wires mixed on the distributor cap.

Checked it 800 times I swear too..... but it was indeed wrong.

 

[FordFreek!]

It shakes a little, but not too bad. Just went out and checked them again though, they're all good. 142536 clockwise all day long... And I drove it again, seems to be getting worse. Has a bad noise coming from under the truck as well, but I can't tell if I hear it around the fuel tank or the oil pan.

 

[oksleeper]

Knock sensor?

 

[shane96ranger]

Did you get a FP reading with the vacuum disconnected? It should be at 39psi. If you still get the 35psi, that's a little low.

 

[RustedRanger]

I noticed you cleaned the IAC...did you do that before or after changing the plugs? I did that one time and there was so much crud in the IAC ports it fouled the plugs. Also the first time I tuned mine up the rotor I got was loose on the shaft (cheapie)