92 22RE drivability problem

[bibbt]

My dad has a 92 extracab 4x4 with a manual trans and 22re motor. It has an intermittant problem that several shops as well as my dad and I have been chasing for about 2-3 years. I have thrown up my hands and would like to hear thoughts from others who might have had a problem like this. Symptom is as follows: After engine is fully warm and in top gear at 55-70 mph, truck will start to miss and surge almost as if it were running out of gas. You can continue to drive it if you are easy on the throttle and are not on too much of a load. Symptom will continue to get worse and force you to go slower. At this point,the missing and surging will happen if driven hard in ALL gears. Engine idles perfect at the time when symptom is present and has never died. Shut truck off and let it sit for as short as 5-10 min. and symptom stops. This problem seems to have no rhyme or reason as to when it will show up. The truck can be driven on all distances from 30-400 mile trips and will go sometimes 6-8 months and not do it. Most obvious things have been checked or replaced. The list is as follows: New:plugs,cap,rotor,coil,distributor,wires,pcv valve,fuel pump,fuel filter,fuel cap. Fuel pressure has been checked and computer has never triggered a check engine light. WHAT HAVE WE MISSED ? Anyone have any ideas?

Bibb T. Gault in San Antonio
also own 85 Excab 4x4 with 300000 miles

[smasheromalley]

This probably wont help you much but the first thing I thought of was my F250 situation a couple years back.

If I was running hard on the hiway 2200-2500 rpms for an extended period I would get the fuel filter light start to flicker on (it was diesel) meaning low fuel pressure at the injection pump. If I stayed in it the light would eventually come on fully and the engine would start to "bog" until I backed off to below 55mph. Then the light would go out and Id be running strong as ever.

It turned out that at Hi fuel demand for extended periods the lift pump was collapsing a piece of the rubber fuel line. I replaced a loop of rubber line with a better piece and a larger diameter loop and it went away.

It would be nice if you could install a fuel pressure gauge at the fuel rail and run with it for a while to see if it is a low fuel psi issue when it does happen.

Good luck!

[bibbt]

Thanks for the tip Smasheromalley ! What you describe is not impossible. Supposedly,one of the shops that replaced the fuel pump for my dad did the exact pressure test that you describe on a 60 mile test drive. I might do this test my self just to be sure. The fuel pump is tank mounted ,so any flexible lines are on the pressure side but there could be some sort of problem like a kink in the rubber line at the fuel filter or the return line I guess. Thanks, at least you gave me a different angle to look at. I also think I will test the pressure regulator.

Thanks,Bibbt in San Antonio,Tx

[bobad]

I had the exact symptoms on a brand new VW Jetta. The dealer jacked around with it for a month to no avail, and it drove me nuts. Finally, I started grabbing wires until I found an intermittent spade connector on the distributor. No amount of cleaning, polishing, pencil eraser, etc would help more than an hour or 2. I wetted the spade terminals with mercury, and forgetaoutit! Not 1 miss until I traded it in!