Hey guys, i have a 95 f150 with a 302.
I have replaced the following in the past 5 months.
Dist cap and rotor with msd brand
Msd 6a box blaster coil
Ambient air temp
Plugs and 9mm motorsport racing wires.
Tps. Iac. Maf. Did a seafoam treatment. Lucas in each tank. New fuel filter.
Oil change with mobile1 synthetic 10/30.
Battery. Smog pump is attached but no longer connected to exhaust.
Flowtech headers. Custom h pipe. Dual magnaflow mufflers.

Here is my issue. The truck runs rough at low rpms. And will bounce rpm between 650 and 1100 or so. In gear at a stop light. I also get surging at lower speeds. My engine light comes on occasionally driving down the road. I hook my scan tool up. All i get is o2 lean. U can smell unburnt fuel.city driving i get about 15 mpg. Can't keep steady idly when first starting on a cold engine. A buddy said fuel pressure regulator. But my test gauge broke. Its $45 for fpr. Or $50 for kit. Is it possible for the fpr to cause all these issues?
I have set timing to 10degrees. But detonation was so bad i had to manually adjust timing. Could that be due to lack of fuel. And occasionally too much fuel?

 

Sure your plugs aren't grounding out?

 

How can i check that?

 

Old plugs i pulled had yellowish tint to them.
But i ran for a year with maf unplugged due to a rip in intake snorkle i could not find til it became the size of the grand canyon. Which is why i got new maf and cold air kit a cpl days ago.

 

Did you lay it out as recommended?1 under 234 etc?
Just had this happen to me, it's in the what did u do today thread, had the boot shorting out at the header, one way to test is to get a glass view plug tester, or pull one at a time when it's off and fire it up and see if any change.

 

Maybe the new MAF is bad. Try unplugging it or using your old one

 

No old one. Core and all. Runs much better.
Threw a code before. Not any longer.
Only code i get now is o2.
Unplugging throttles WAY up. Then stalls on me. Unless i manually keep it running.

 

You talking a standard plug tester? Or is this something specialized that replaces the plug itself? I did route them according to diagram. They maybe moved around on me... engine is shakin a bit.

 

Just standard, when you set the timing, did you pull out the SPOUT connector?

 

Pretty sure was the spout. Green and red wire into a plug that did nothin just a cap. On top of left fender/wheel well.

 

Idle Ar Control Valve

 

Freshly replaced. Happens goin down the road at 40 mph... slight bucking

 

did you replace with new or used. I had the same truck, replaced with a used one did the same symtoms urs is, replaced with a new one, Never had a problem after that

 

If you're getting knocking at 10* static timing, and the O2s report lean - then I'd suspect a lean condition.

I'd get a new fuel pressure gauge and check that.

 

For what its worth, if you haven't already, check for vacuum leaks. Air that enters the engine without the MAF knowing about it will cause a lean condition and can cause "lean pops" (sounds like back fires sort of).

So look anywhere after the MAF. Intake manifold gaskets both upper and lower, PCV system, any of the vacuum related components, etc.