Running Rough under throttle

dr.evil

Registered User
Hey-
Im new here, looks like a cool place. Ive really enjoyed the FAQ while learing about these cars. I have a 1990 SHO and my friend just picked up a 1991 S/C 5-speed.
Anyway, when we test drove it, it felt fine. Didn't get on it any, but it sounded good.
Well after he paid for it and were driving it home, it shutters and knocks when anything over 1/4 throttle is applied. Feels like it is going to die. I think it is fuel related, but could be wrong.
We cleaned the MAF and put some good gas in it w/ a can of injector cleaner and drove it home. So next on the list is a fuel filter and new motorcraft plugs.
Just wondering if anyone else has any ideas? I will post the codes we pulled from it later tonight.
Thanks for the help.
 
well im not the best and im sure others will chime in, but first always make sure it has good plugs and wires. plugs-motorcraft or autolite double platinums. just like stock, no bosch or any other plugs. and wires either magnecor or factory replacment wires. i have autolite double plats and magnecor 8.5 wires and it runs great. used to stumble when i bought it because it had bosch plugs and like napa wires or something hahaha. but i would check that first and make sure the gap is good on all of them. EDIT: but hmm read it again and the knocking is wierd, maybe it is fuel related. after filter and plugs i would also check the fuel pressure and see how its doing.
 
Alright, here are the codes we pulled:

KOEO:
Hard Codes:
522
Continuous Memory:
121
56
212
214
556

KOER:
412

Are these any help? I don't think anything has been replaced under the hood. It still has the original upper rad hose! Could the TPS be the problem if not the plugs/wires? Do the coilpacks or DIS tend to go out on these cars after 100K?
 
dr.evil,

Keep in mind that these codes can either be defining or can be caused by other problems (not necessarily a bad part).

121 code is a TPS out of range
212 SPOUT Connector Fault
214 Cyl ID (Cam Pos Sensor)

Looks into more of these later.

M Randolph
in SoCal somewhere in Kali~fornia

-95 Thunderbird SC/5-Spd
-69 GTO 400/T400
-67 Chevelle SS 396/4-Spd
-66 Nova SS 283/T350
-57 Ford Fairlane 2 Dr H/T 312 SC
-Searching for a 69/70 F/B Mustang
 
Well today we were changing the plugs/wires, and found the #3 wire was not fully pressed onto the plug! So after changing the plugs (what a pain that is...and I thought the SHO was tough!) wires, fuel pump, and cleaning the IC and tubes, we fired it up. It ran rough and died. Checked the wires to see if they were correctly hooked up. When I first looked at the coilpack, I thought it was:
1-2-3
6-5-4
The back of the 6 was rubbed off and looked like a 5. So it was actually:
1-2-3
5-6-4
Kind of strange...but it was an easy fix. After that was straightned out, fired it up. Runs beautifully now. Will definatly give my SHO a run for the money!
 
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