My "new" SHO is driving horribly!! Help me!!

[ponchodan]

I just bought a 1992 MTX SHO with 97K miles on it, and it bucks and surges like a rodeo bull! It was fine at first, but after driving it for a while, the "check engine" light would turn on and off and and the car would start bucking and surging like crazy. It even shuts off some times! My RPM's fluctuate at idle and the car randomly shuts itself off. It really feels like it is screwed up and struggles to keep itself running. I can't even tell any of my friends that I bought it yet because I am too embarrassed that I may have gotten taken for a ride on this deal (even though I practically stole this car). I bought it off a dealer that got it from another bigger dealership after it was traded on a new car. I bought it "as is". For the first little while, this thing pulled wonderfully all the way to redline then the trouble began when after some full throttle applications, the light would pop up. Then all **** broke loose. Please tell me there may be a possible easy solution to my problem! I need your help badly, I am bumming terribly

. Thanks to anyone that can point me in the right direction!

 

[Prophet78]

Start with new plugs and wires. Go to the dealership and pick them up. Gonna cost ya. Don't go with anything other than motocraft. Double Plats.

-jeremy-

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mailto[email protected][email protected]</A>
'93 Red ATX "Red Phoenix"
Rebuilt "Ford Quality Rebuilt Transmission" w/ Shift Kit
SHOShop CAI W/K&N
SHOShop Front STB
190 LPH Fuel Pump
Koni Inserts
Eibach Springs
Blazer Modded Fog Lights
Taylor 8mm Spiro Wires
SHO Filler decals
Fish Tanks
225/50/16 BFG GeForce T/A KDWS

 

[shomaster]

Same thing used to happen to me. Its really scary at first. but replace wires and plugs and you should be good.

 

[SilverSHO]

If it shuts itself off randomly while you're driving down the road, it's probably the crankshaft position sensor (CPS, or CKP if you're PC

). Those have a habit of dying not long after the water pump craps out. The reason is because the water pump sits directly above the CPS, and when it starts leaking, it leaks onto the CPS, causing it to short out and fail. So you might want to take that into consideration.

As for the bucking and surging, mine does that too. Common cause of this is a clogged intake air control (IAC) valve, which is on the inside of the intake manifold, next to the throttle body.

To find out why the Check Engine light is flashing on, you'll have to pull the codes. The EEC-IV test connector is on the passenger side of the engine bay, up near the firewall. It's a trapezoid-shaped plug with a single-wire plug hanging next to it. You can get a EEC code reader at Wal-Mart for about $25, or you can use a jumper wire and connect one of the contacts in the big test connector with the little one. There's a procedure on shotimes.com that shows how to do this.

Good luck with the SHO, and may the Schwartz be with you

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Nick
Lt. Titanium 90 136k
Coneless, ACCEL 8.8 stainless steel wires,
SHO Shop torque limiters, Cherry Bomb Turbo II mufflers
AIM: loudog6491, TitaniumSHO

 

[noSHO]

I looked at a car in PA that sounds JUST like that. It was a green 91 in Uniontown, same story, same problem. Like Nick said, sounds like the CKP to me.

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-Dave
Green 92 80k coneless, fishtanks, K&N panel filter, SHOnut reinforced motor mounts, SFCs, Perf. Plus Y-pipe, Summitracing Turbo Mufflers

[email protected]

 

[bigdoggee]

try fordpartsnetwork.com they had pretty good prices for the sparkplugs and wires... Also, do you have oil in your sparkplug wells?

 

[Fine89]

Sounds like mine after I hosed the engine down. Did the dealer clean yours? I had the same symptoms. Like others said, most likely plugs/wires (was my fix). If you do it yourself, use dielectric grease (any auto store) and coat the wire contacts.

Are you in the LSSHOC club? I guess Wayne is sorta near Philly? Good Luck

 

[sdpatt]

I'm sorry to hear about your first experience with a SHO being a bad one. If you are getting the CHECK ENGINE light, it would serve you well to check the EEC codes. It only takes a 6" piece of wire and about 5 minutes of your time. Don't guess and throw money at a problem you don't have. Learn how to diagnose the CHECK ENGINE light error codes here:
http://216.92.187.145/SHO3eeccodes.html http://216.92.187.145/references/eecarticle.TXT http://216.92.187.145/SHO3eeccodes3.html


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Scott

1991, 253K miles, glass hood, police grill, SVO shifter, Catz fogs,
K&N, 73mm MAF, Superchip, PP Y-pipe, Borla cat-back, 190 lph pump
Eibach/Tokico/polyurethane, SHO Shop front & rear strut braces,
16x7.5" Moda R1, 225/55ZR16 Bridgestone RE730, -1 deg camber x 4,
Class II hitch, Silver award at the SHOklahoma Car Show

 

[GOLFSHOMAN]

pull your codes for sure. i had a throttle position sensor cause a simular bucking/idle problem.

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SOME TIMES IT CAN MAKE YOU CRY, BUT YOU GOTTA
LOVE IT.

 

[ponchodan]

I forgot to mention that when the car fights to keep itself running at idle, that the intake sounds like it is spitting out air! I have had cars before with horribly fouled plugs and they didn't run like this one, this thing is scary. When driving, the tach would just go nuts, and the car was bucking so violently that when me and my friend (the only one that knows about the car) got out we had to get adjusted to standing on steady ground. I ordered a code reader from JC Whitney last night to try to get to the bottom of this mess. Thanks for your help guys.

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1992 Emerald Green MTX SHO
1992 Pontiac Bonneville SSEi
1998 Pontiac GP GTP - runs mid-13's

 

[fredhurderjr]

vac leak? IAC?

 

[ponchodan]

Now the car won't start at all, I tried cranking it for a while with no luck. Now I can't even read the codes!

 

[91 SHO PLUS]

Geez, how much did you pay for that POS!

 

[ponchodan]

Yeah, but anyways, I was able to run a key-on , engine off test today. It showed one hard code, a 543, meaning that I have a fuel pump circuit failure. Does this sound about right? Could this be causing my problem?

 

[ponchodan]

BTW, I did get it started today and before this KOEO test, I had run one that pulled up more codes, but they weren't hard codes. They included several fuel pump circuit failure codes, a manifold pressure code, a MAF sensor low voltage code, and a cylinder identification circuit code. Does anyone with experience have any guesses as to what is going on? That test was also a KOEO test, I didn't have time to run a test with the engine running.

[This message has been edited by ponchodan (edited 12-14-2001).]

 

[pjtoledo]

put a timing light on that engine, see if you are getting spark at the right time. my bet is the crankshaft position sensor, with plugs and wires making it even worse.
Perry Toledo,Ohio
92 MTX 233,000 miles
95 MTX 79,000 miles
original ownerof both, do all my own work

 

[sdpatt]

It could all be due to the cylinder identification (CID) sensor, also known as the camshaft position sensor. This device is mounted on the passenger side end of the rear bank's exhaust camshaft. It is held on by two 5.5mm bolts that are tough to reach. The sensor is about $30 from most auto parts stores.

Scott

 

[sho_can]

Well well well... I finally found some one with the same problem as me! Does it do it after its been running for a while? mine would acted up just like that after a good warm up, I changed the CID(Cam sensor)and its been running fine after that, acually better than it did before, sence you got the same codes i did, i would try the CID, it's not all that costly and you could probably change it your self, it's a PITA.. but it can be done. I think I'd put money on the CID!!! let us know if you change it and if it fixes your problem. I would like to know, it solved mine!

 

[bigdoggee]

Hey Ponchodan,

If you are interested... I have a set of used 90MTX wires and 6 Bosh Spark Plat Plugs that I would be willing to part with for next to nothing!! My brother bought the wires for me, but I have an ATX so they don't fit. I bought the plugs from Autozone and they have less than 2 miles on them!! Could be a very cheap alternative to see if in fact the wires & plugs are your problem!! Send me an email if you are interested...

 

[ponchodan]

Thanks to everyone for all of your help, I really didn't expect these kinds of helpful responses! I've ordered a cam sensor and will install it on either Monday or Tuesday. Hopefully it will solve most of my problems with the car. Now if only I could figure out what those peculiar popping/rubbing noises are from both sides of the front of the car when I turn the steering wheel at low-speeds! I didn't even know this site existed when I bought my SHO, but I sure am glad I found it! Thanks again.

BTW Doggee, you have mail.