New here, having troubles with the wife's pickup, which she just bought.
Did some searches through the TSB's and forums first, found some clues, but no outright solutions, so maybe you guys can help.

I'm thinking these symptoms are related,but maybe not, see what you think. I don't have a reader or scanner but I saw the post on how to pull codes without them, haven't yet. No CEL on, ABS light on steady.

Pickup has 113,000 miles. Engine is clean inside and out, runs smooth, no misses bogs etc. Trans fluid is clean, not burnt, found no trash in pan. Supposedly rebuilt fairly recently, and looks it.

Here's the symptoms:

1. The trans has a harsh 3-4 shift. Part throttle, shifts correctly timed,
1-2-3 are smooth, converter lockup between 3-4. Full throttle, shifts are correctly timed, 1-2-3 are firm, but not harsh, converter lockup between 3-4, 3-4 shift is still harsh, but less so under the additional torque. There is no shuddering, slipping, or overrun between any gears. Engages quickly hot or cold, forward or reverse.

2. When cold, the idle "hunts" until closed loop, then stabilizes at 1100 rpm. Will die occasionally when the rpm drops. A/C on makes it worse. It starts easily, runs smooth, ie no missing or running rough.

3. When warmed up, or closed loop, the idle is stable but high at the aforementioned 1100. Dropping it in gear causes an increase in IAC, have to stand on the brakes to hold it. When placed back in park, the idle flares momentarily, then returns to 1100. The A/C cycling has no abnormal effect when warm.

So far, I've replaced the TPS, checked the MAF for contaminates etc., and checked for vacuum leaks with carb spray, found nothing. Like I said, the engine runs good, pulls good, no black smoke, or roughness.

I'm thinking the there's no converter unlock between the 3-4 shift causing the harshness, and the idle problem may be related to that also. At low speed, around 30 or so, the 3-4 is hard as a hammer. I see no indication of a partial or complete lockup on the tach after it's in 4th, the lockup between 3-4 is easily seen.

Any ideas? Thanks.

One other thing, it is an extended cab, any harness troubles on the '95's? The TSB says '98 up, didn't spot any TSB's on the earlier trucks. This one's spent it's entire life in West Texas, no road salt etc. although it does rain every few years lol. Thanks again.

 

Welcome to FTE.

You've been busy on this puppy & have done some good trouble shooting. You may have more than one problem.

The clue about idle being worse with the A/C on sorta makes me want to suspect the IAC, as it's responsible for maintaining idle speed. Maybe try removing & cleaning it with a plastic safe spray cleaner & see how it goes. cleaning may not last, it didn't for me but was a good trouble shooting step.

On the tranny shifting, is the speed-o unsteady/acting out, or the cruise control acting out, like not wanting to take a set, or randomly dropping out, the ABS light being on, or the tranny shifting acting out are clues, so put the rear differential mounted ABS speed sensor on your suspect list, as all of those things use it's PID output to do their things & it's a common problem part. Low cost, quick & easy to replace, one 10mm bolt 25-29 ft/lbs. one electrical connector. Located front center atop the rear differential. Lube the new "O" ring before installation.

Let us know how it goes.

 

Good to meet you Pawpaw.

The speedo is rock steady,and it's not equipped with cruise. The rear end sounds a little bit loose, has a mild clunk and an almost inaudible whine, so it's possible the sensor is covered with metal shavings or otherwise damaged. It's on my list to replace, but I'll have to order one. Went to five parts stores hunting the TPS, and none had the ABS sensor.

I've considered temporarily clipping the wire to the TCC solenoid,or pulling the pan and unplugging it, just to see if the 3-4 shift smooths up. I hope the OD clutch isn't screwed up. $$$

The wife is moving another notch up my you know what list for not getting me to drive the thing before she bought it. But, over all it's a pretty decent looking/running pickup, so a few bucks here and there won't kill me.......much. lol.

 

Hold on, I wasn't suggesting you replace all of those things, just to put them on your suspect list for testing/check out. So don't throw parts at the problem, take the time to do a proper trouble shoot, get a positive result, Then replace the faulty part.

Maybe begin by running this puppy by your favorite autoparts store for a no cost computer trouble code scan, as any stored codes could offer up good trouble shooting clues. The computer can have pending codes stored that haven't happened often enough to have the computer turn the CEL on yet.

 

Think I'll dig around on Ebay and buy a good used scanner so I can see the sensor parameters in real time, take snap shots, codes etc. Had five on my watch list a while back, got distracted and didn't buy one. Since the newest thing I own is a '97, a scanner will likely come in handy anyhow. Hard to work on most anything these days without one, and I hate poking around with a multimeter any more than neccessary.

A steady diet of chasing bad grounds, separated circuit boards, screwed up wiring and glitches is the main reason I quit the auto repair business about 15 years ago and went to work on oilpatch pumps. Now even those are PLC controlled lol............

 

Roger on using a scantool rather than back probing with a multimeter. I've had my Actron CP9145 scantool since 05 & it's finally paid for itself with the last repair I just finished on my 94 Taurus. The computer was intermittent, randomaly killing spark, the mother board had so danged many cold looking solder connections that I gave up on the idea of trying to reflow questionable ones, est 75% looked questionable!!!! Lots of solder ball splashes under the conformal coating around the connector contacts to the mother board that were large enough to short between the races, real sloppy workmanship. I sure wouldn't want to try & make a living chasing things like that!!!!

Keep us posted on your findings.