Hi All-

I did a search under "bucking" or "engine misfire" and I still haven't found a solution. I have a 1987 pickup with a carburated 22r, 4-speed, California emmisions. About 40K on a rebuilt motor, with a new factory EGR and cat that have less than 20K miles on them. Igniter changed about 60K ago.

I was driving on Saturday and suddenly developed a severe miss- almost a "buck"- plus lack of power/acceleration and inablity to use sudden throttle. I could feel it happen instantly. At higher throttle settings, it just growls and loses power. It also pings slightly, even on gentle acceleration.

It still starts easily, but the idle is now a little lumpy and inconsistent, and under load runs like crap throughout the rev range.

No coolant loss, no coolant in the oil, no overheating.

Per the threads I've read on here, I've replaced the fuel filter, cap , rotor, plugs, plug wires, and checked the mechanical fuel pump to make sure it's working. It checks out. I also tried running it with the gas cap off to see if the vent on the cap was blocked. No change. The old spark plugs, while worn, were a nice coco brown color.

I also took a look at the vacuum hoses and all are still supple- nothing with any cracks I can see. I don't have a vacuum pump, but I did the "suck it and see" method with the vacuum advance, and with one port, you can feel resistance and hear the ignition plate in the distributor move, with the other port nothing- no resistance, it's just like sucking on a straw in the open air.

I don't particularly want to get into the massive parts swap to figure it out, (money is an issue and I've bought all the tune up parts so far) but wanted to see if anyone else had experience with this? Not sure if it is coil/distributor related, (specifically vacuum advance), carb related, or emission control related (i.e. a plugged charcoal canister?)

Thanks in advance for the feedback.

 

If your carb has the auxillary accelerator pump on the it, pull the vacuum hose and see if there is gas in the vacuum line. Its common for the diaphragm to get a hole in it and let fuel into the vacuum lines, that will cause a miss and lack of power

 

Thanks! I'll check tomorrow.

 

I am having almost the same problem with my carbed 87 22r. Except mine has a lil power but very very lil power. I am thinkin distributor. Havent got around to distributor yet as money is an issue right now. But if i fix mine i will let u kno how i fixed it. And if you fix yours please let me kno how you fixed it also.

 

Found out the problem- the timing chain stretched and the tensioner hiccuped enough for it to skip a tooth. I was lucky that it didn't skip more than that and bend the valves. Sort of a bummer for an engine that only has a little over 25K on it. Sadly, I don't have the money to do a double row conversion, so I had to just have the timing reset, then hope that it doesn't happen again before I can save the money to convert over to the double row setup.

 

Thank you!

I was wondering why my truck felt a little down on power lately. The diaphram was definetly leaking a ton of gas into the vacuum lines.

 

Thank you. I will b sure to check that.

 

not to hijack this thread but do you pull off the vacuum line when running or parked?

 

It was parked with the engine off. If the diaphram is leaking, the inside of the line will be wet. I just blocked off the line with a bb from a bb gun.