Sputtering Continued

[Ripper]

'85 4R 22RE

A month or so ago I encountered occasional sputtering at lower RPMs when accelerating from a stop. I believed this had something to do with bad gas, cold weather or something they mix in fuel. The problem has now gotten worse. I have changed plugs, cap ,rotor and checked all the obvious stuff but no solution.

The idle has gotten rough but until the engine warms up the sputtering is not a problem. As soon as I see the temp gauge rise, the sputtering at low RPMs begins. If I take off from a stop and use WOT, the truck accelerates without issues. I think that power overall has decreased, even at highway speeds, and the fuel mileage has suffered.

Has anyone had this problem, or are there any ideas ???

Would a compression/ leak down test be worth the $$

 

[Bogo]

How would sputtering be effected by the rings or valves being worn?

On the other hand checking the vacuum system would be in order. If the vacuum hoses have never been replaced I'd seriously consider doing them. Change them all and inspect where they connect to for cracks at the ports.

I'd also run a bunch of carb/injector/valve cleaner through it.

As for other stuff to do, who knows. I'd consult the FSM and go down it's lists. Check the FAQ thread for links to various FSM versions on the web if you don't have your own copy.

 

[raydouble]

When was the fuel filter last changed?

You mentioned the cap, rotor and sparks........ how old are the wires?

Has the idle/timing been checked?

 

[Turbo Turtle]

It was months before I finally figured my problem to be related to a plug wire breaking down. Brand new set of OEM wires. New everything else and still the miss. The plug wires had only been removed one time since being installed. It was this first time the wires had been pulled that I had an issue removing one. I later ascertained the forced removal of that one wire caused it to break down at the connection just inside the boot.
Hit a store for one long plug wire and switch it from cylinder to cylinder. I didn't need to do the switching because I had a suspicion that my number three wire was the culprit.
Problem solved, but how long did it irritate me. A while!

Bob

 

[Ripper]

Thanks for the replies!

I think I may have to check my cables after reading that; NEW does not always mean good.

 

[Ripper]

The sputtering was caused by a bad O2 sensor. The sputtering is gone now but I do have a miss at high RPMs. I didn't realize it until I tried to get smogged. I am hitting 250-260 HC at 2500-2800 RPM (allowed 220). I don't have any other measurements, the new smog stations only have GO/NO GO printout.

 

[morganism]

sounds like the old egr sticking problem. throw a vac line on the top port, suck, and bang (lightly) on the top of the EGR. hear a rock falling down? that was it. sounds porn in the description, but your'e in Vegas anyway