I have been struggling with a hesitation/stumbling problem for 2 - 3 weeks. It actually got worse as I worked on it. The problem was fuel restriction at the banjo fitting on the fuel rail. Your '87 like my '88 probably has a fuel damper on the bolt. 89 - 95 don't have this kind of bolt I guess. The passage way was blocked on mine by the copper washer used to prevent fuel leaks.

 

Quick question, not to hijack your thread or anything

But is the idle not supposed to increase once the jumper is removed?

I'm having a similar issue with the toyota I just bought. I checked the timing and it was set 5* ATDC, so i set it back to 5* BTDC, and it drastically increased its power, but again, it falls on its face around 3750RPMs, and can just bearly make it to 70mph, and we're talking really pushing it to do so on flat ground. When I put in the jumper, the idle drops 200-300 RPMs, when removed, it pops back up to 1000-1100 RPMS. The power problem almost acts like there is a vac leak, but I've checked all the hoses. And when pushing in the clutch every once in a while, the RPMS will fall too hard and it will die.

When you did this Junkers, did you have any increased valve noise before replacing the gasket. My 22RE is making horrible what sounds like valve noise, but just 1 cylinder is having the issue. Clearances are all set correctly, compression is perfect, spark plug color is great. I am not sure if the knocking sound and power are related, but it would be nice if they were.

Its supposidly a rebuilt engine, i have a feeling the PO didn't know what he was doin.

 

I pinched a soft line on my fuel supply, and it did exactly what he described, plus it revved just fine in neutral. I dropped the tank and found the kink I had created though, straightened it out, and viola, no more cut-out.

 

Apologies for dredging this up but it should be nice to attach this info to the right thread...

So my main issue is resolved, but I can't say exactly what fixed it.

Quick Summary- After timing chain, oil pump and water pump replacement, cleaning the upper intake and TB, moving the AFM and battery, installing an electric fan, and making the necessary adjustments to TPS/Idle/Timing, the truck pulls past 4500RPM.

To recap, my main issue was that at full throttle the truck would hit 4500RPM and bounce back like a slow ignition cut at max RPM. If I lifted off of the throttle it would continue past 4500, but the truck would have very little power beginning at 4000RPM.

• After adjusting TPS and idle there were no improvements.
  
• After replacing all the ignition components except the distributor and ignitor (actually just the coil, plugs, wires, cap and rotor) there was no change.
  
• After setting timing to 5*BTDC I actually lost a bit of power.
  
• After adjusting valve lash I had a bit more valve noise, but no improvements.
  
• Basic fuel flow tests didn't appear to point to a fuel issue, but I was averaging about 16 MPG.

I couldn't confirm that the cam and crank were in proper alignment. Then I noticed an RPM dependant oil leak (as high as 1qt per 100 miles under heavy load such as highway speed) at the oil pump. That was enough to convince me to dig deeper.

I replaced the timing chain and sprockets, water pump and oil pump. I also moved the AFM and battery (though I'm using the stock airbox/filter until parts arrive) and installed a Taurus electric fan. After reassembly, it pulled beyond 4500 RPM but still sluggishly. After finalizing timing/idle adjustments it pulls better at low end and above 4000RPM without much change between 2500 and 3500.

I've left out an important part that may be the key (no pun intended). The woodruff key that indexes the crankshaft pulley was worn on both sides and the pulley and crank were worn such that the pulley was slightly (~5*) advanced. I replaced the key and thought it was alright, but when finalizing the valve lash adjustments I noticed that the crank index was at TDC, but the cam was not yet. I trust the cam more than the crank and painted a new timing mark on my pulley. I would be curious to know if this is common, or if there is a good fix for the worn keyways.

I guess it was a rewarding couple of days work (I took my time and cleaned 15 years worth of leaked PS fluid and 2 years worth of leaked oil off of everything while I was at it. Now I just need to finalize the intake and install a thermostat for the fan...

About the only thing that seems to have suffered is warm start, but that may be because I've finally got the idle set at 750 vs the 1150 it has been set at since I bought it...

 

Valve adjustment?