My 22r has started bucking like crazy under heavy acceleration and losing oil pressure at highway speeds. I pulled the (NGK) spark plugs last night and noticed white powder building up on the tips but I haven't adjusted the carb in a month & the bucking just started. The truck runs great at idle & in town but is not really highway-ready anymore. Timing is dead on, no vac leaks (tested with carb cleaner). What would cause bucking & losing oil pressure-- could it be as simple as bad gas?!

Last night I installed OEM plug wires and 1/2 tank of premium fuel. This helped against the bucking but the truck still shows declining & variable oil pressure at constant speed. The truck has have a new (5,000mi) long block and new Weber 32/36 but the rest is (for now) stock. Could constricted exhaust from an ancient catalytic converter kill my oil pressure at speed? Please help. <img src="/forums/images/graemlins/cheers.gif" alt="" />

Nothing? Even another person's idea might help here. Instead of ~75psi oil pressure on the highway I am seeing variable pressure and reduced engine performance. NEED HELP.

You sure that the oil pressure doesn't drop when the engine bucks? ..that would be normal as the rpms drop when the engine bucks.

As for the bucking.. if the weber idles fine and comes off idle fine, then it sounds as though theres not enough gas in the float bowl. Either the floats are adjusted too low, or you don't have enough fuel pressure. If you have a fuel pressure regulator installed (which you should) you want it around 3 or 4psi.

If its too low, then the intake will draw more gas than the fuel pump is putting into the float bowl and if your at full throttle for more than a few seconds you won't get gas until the pump catches up with you. Same thing happens if the floats are too low.

Hope that helps,

Scerb

Thanks for the reply! I have this inline fuel pressure regulator cranked to 5.5# because at lower psi I can't get enough gas. Maybe the cheapest fuel pressure regulator wasn't a good choice? FPR
I will adjust the float level tonight & see what happens. Any thoughts on why oil pressure would vary so much at steady speeds? Anybody recommend a better fuel pressure regulator for the 32/36? <img src="/forums/images/graemlins/cheers.gif" alt="" />

Try temporarily removing the pressure regulator and see if that helps. Its possible something is clogging it.

An update: I pulled the oil pan and found a piece of the plastic timing chain guide in there! I think the plastic was clogging the oil pump filter sieve and costing me oil pressure. This is a new motor and was supposed to have metal guides-- <img src="/forums/images/graemlins/angry.gif" alt="" /> The builder has agreed to send me a new tiiming chain with metal guides but now I have questions about the long term durability of the engine & I wonder if the rest of the motor is built as advertised, with upgraded performance parts to produce 134hp or if I just got a (expensive) stock motor. This is the same engine that shipped without galley plugs & without hooks to lift it into the truck. Very Frustrated. Any ideas on how I can be compensated for this-- or do I just chalk it up as a learning experience?

When was the last time you replaced the fuel filter? My '85 pickup did this exact same thing on me on a Sunday evening 150 miles away from home. It would idle fine and drive at slow speeds ok, but anything involving a lot of fuel and highway speeds would cause the engine to buck. The fix was a $5 fuel filter (located above gas tank and easy to replace). If you have no idea when it was last replaced, this would be the first thing I'd be doing.

Read your warranty. Who was the rebuilder? The rest of us might need to avoid them.

If it was JFE Engines aka 22R.biz aka 22RE.biz, he's an <img src="/forums/images/graemlins/butwiggle.gif" alt="" /> Out of Washington.