Please help, rough idle & NO POWER 95 ATX... tried everything, still problems.

[ACV1081]

OK, here's a brief history on what's happening... I have a 95 Automatic 135K that is my mom's daily driver. It developed an increasingly bad "chug" at idle and during acceleration that has to led to a huge headache. The car idles and just sort of misses and sounds like there is an exhaust leak. Increased throttle and RPMs seems to lessen the issue, but once you drive the car it has ZERO power and stumbles/sputters. I am wondering if it could have skipped a tooth on the timing, but I'll follow with a list of things I tried after researching posts here and other places... bottom line, is I'm ready to drive the car off a cliiff.


BTW,
Currently NO codes, had an EGR (332) but got that resolved with a new EGR valve.


What parts I've swapped:
ECT sensor
Cleaned MAF, tried a known good extra
DIS
TPS swapped out with good extra
Checked plugs/wires/firing order all have been replaced <15K ago double platinum plugs
Coilpack
CID-Cam sensor
Checked everywhere for vacuum leaks, broken wires, hoses... nothing found
New fuel filter
Fuel pump comes on strong is not very old
IAB-swapped with new clean working unit
Cleaned intake
Cleaned sensor in the bottom of the airbox/ tried diff one
Secondaries work
New alternator
Rod bearings have been done


That's alll I can think of, but I'm really sick of having this car just sit... if you can think of anything that could cause such a poor running condition with no codes please tell me. Like I said before, it just sounds like it's not running all 6 cylinders and just sputters and chokes when you try and drive it and accelerate. Prior to this the car ran great and was quite quick. Thanks in advance and sorry for the long post.


Adam

 

[93superSHO]

Check your ground wires. Also, do cats get red hot? With the car running have someone give it gas and listen for rattleing from the cats. They could be plugged up.

 

[TicoSHO]

I had clogged cats and mine was acting very similar to what you have. Does it stall at all? It started out as intermittent as dipping of the RPMs, to stalling every once in a while, to stalling two or three times each trip. Power was also down considerably. When my cats finally went, it would idle great until it got up to temp and then would just stall out. $500 later it ran smooth and strong again.

 

[qiksho]

I would also suspect a clogged cat from your description and no codes.

What brand plugs did you use? I have found that non-motorcraft plugs do not work well in the SHO. Two of the SHO's I bought had other brand plugs in them and they went bad in less than 5k. I believe that the Motorcraft is now been replaced with the autolite agsp32pn or fn? something like that.

I would also check fuel pressure at the rail incase u possibly have a half clogged fitler.


Good luck

 

[ACV1081]

I would also suspect a clogged cat from your description and no codes.

What brand plugs did you use? I have found that non-motorcraft plugs do not work well in the SHO. Two of the SHO's I bought had other brand plugs in them and they went bad in less than 5k. I believe that the Motorcraft is now been replaced with the autolite agsp32pn or fn? something like that.

I would also check fuel pressure at the rail incase u possibly have a half clogged fitler.


Good luck

Thanks for the heads up guys... the fuel filter is new, and the plugs are motorcraft. If I remove the y-pipe would that allow the problem to go away? Just to check? I used to have 10 ATX pipes, but of course have 0 when I need one myself



Adam

 

[qiksho]

Adam,

You should be able to take it off and inspect it....blow air through it, etc....

If it is clogged it should be fairly evident.

I would also check the catback if you think chunks have fallen out of the cats....a shop vac hooked up backwards has worked for me.


However if you did have another known good y pipe to try that would be another way to test.

 

[SeanMc]

Mine kinda did that when I had one clogged cat. Now I'm wondering how I would get that stuff out of my mufflers.

 

[dpsutphin]

If the problem went away for a bit when you replaced the fuel filter, then returned, you probably have some trash in the fuel tank that is partially clogging the filter. Had to change mine 3 times to get the problem to go away for good. But 3 fuel filters is a lot cheaper and easier than dropping and cleaning the tank.

Also, follow the wires from the fuel injectors back as far as you can, especially where they contact the intake, or anything else metal. One bare spot can cause the symptoms you are describing as well. A couple of strips of electrical tape will fix it if you find a bare spot.

All that is relatively easy, cheap, and won't take long before you start looking at the catalytic converters. Those can get into the big money real quick.

 

[SonicRiot]

Take the Y-pipe off and run it open. If it runs fine in open loop, inspect the cats.

Cant afford new cats? Hollow them things out with a big ol' screwdriver!

If the timing jumped, you'd most likely hear a loose chain or tensioner on the rear of the block or a loud whine in the front of the block. Also, the engine most likely wouldn't even start. A simple compression test will eliminate this possibility, a leakdown will pinpoint it.

 

[ACV1081]

Take the Y-pipe off and run it open. If it runs fine in open loop, inspect the cats.

Cant afford new cats? Hollow them things out with a big ol' screwdriver!

If the timing jumped, you'd most likely hear a loose chain or tensioner on the rear of the block or a loud whine in the front of the block. Also, the engine most likely wouldn't even start. A simple compression test will eliminate this possibility, a leakdown will pinpoint it.

Thanks all for the insight... I'm going to have a chance to mess with this probably Monday night, so I'll let you all know what I find out. I'm doing a fuel pressure test and some other odds and ends tests, but if that doesn't yield any info there's a guy locally who can diagnose things that others just can't figure out so I may suck it up and take it to him. Best thing is he's pretty inexpensive, so it won't hurt the wallet too much and my pride will be all that takes a hit.



Adam

 

[revhardSHO]

Check fuel pressure at the rail. I dont remember the spec, I think is somewhere around 29-30 psi at idle.

 

[qiksho]

Check for a clogged cat....my guess is that is what is causing your problem as it won't throw a code....

 

[SonicRiot]

Did '95's use post cat O2s?

 

[ACV1081]

Well 2 mechanics after me later I I I I figured out the problem... MUCH to my and the other mechanic's embarassment. Whoever suggested plugs/wires I stand corrected. I should have triple checked them to be sure, but it was cold and winter in Iowa. I found the wire closest to the EGR valve on the rear of the motor to look oddly raised. Couldn't get it to seat and found the rubber boot had seprated and obviously was not allowing for a constant or good spark. Also, a couple of the taylor 8mm wires were corroded at the coilpack and just overall not very impressive for their cost and age. The double platinum plugs had been hosed with unburned fuel so for now I patched it together (was diagnosing so didn't want to go all out) and put in new plugs and swapped out a couple of the worst wires with donors from my garage. Roasts through all the gears again and is almost ready for sale I vow to not allow either my dad or mom to own any more SHOs as I'm tired of being the resident SHO expert and this turned into a 6 month ordeal. I'm so glad it's over and thanks again to all of you who posted




Adam

 

[SonicRiot]

Hey, we all make mistakes. It's how we learn... to never embarrass ourselves again and to show up the next guy!

My buddy bought a NEW IAC for his 95 Bronco and came to me asking me to install it. I asked him why and he showed me his lumpy idle and **** poor acceleration. I told him he had a misfire or a vaccuum leak. He didn't believe me, so I pulled out a can of contact cleaner and sprayed down the intake manifold for leaks. When I got to bank 2, a huge flame erupted when I sprayed it down. I found a spark plug wire out of the loom melting to the new headers, arcing like a friggen rainbow with a *** of gold at the end!

Back to the basics!

 

[ACV1081]

As pathetic as it was I have never been so happy to resolve a problem... it was like I had never worked on an SHO before, but with these cars it can always be something new it seems. Thanks for making me a little less like an idiot



Adam

 

[djsSHO]

I had a similar issue occur with the Taylor wires. Had 2 go bad with less than 10k on them. It ran like crap but no codes. Put a brand new set of motorcraft's on there and it ran like a champ again.

Glad you got it worked out.

 

[ACV1081]

I had a similar issue occur with the Taylor wires. Had 2 go bad with less than 10k on them. It ran like crap but no codes. Put a brand new set of motorcraft's on there and it ran like a champ again.

Glad you got it worked out.

What a joke... those things are not that cheap either (taylor wires.)




Adam

 

[SonicRiot]

mine were $80, I think. no problems thus far...

the MCs were well over $100 IIRC...

 

[revhardSHO]

Good work!

The AC Delco wires are OEM design (even down to the covering over the wires), I have had them on my 89 for about 40,000 miles now, no problems. Last time I checked they were about $46 dollars shipped from Rockauto.com.