help-- I think my car is getting mad with me!

93GTDIN · 09-11-2002, 11:45 PM

I was driving on the highway today about 60 mph, when all of a sudden, my tach needle drops drastically to about 600 RPM, and for lack of a better description, bounces around. Eventually it popped back up to about 1700 rpm or so and ran fine for two minutes. DId the same thing again,and when the rpm's shot down, the engine seemed to miss horribly, maybe even backfire, but it was relatively quiet. Only think i'm confused about is why when the enginespeed dropped, the car didn't slow down. My first suspicion was ignition so I made sure all the wires were on pretty good. After inspecting the motor and deciding I couldn't see anything wrong, I drove it home and it didn't misbehave. Ten minutes after I arrived I took it for a ten minute (approx) drive and it did fine. So as of the current moment, I havent been able to reproduce the problem. Here are some possible problems I have conjured up, please help me add/dismiss theories.

-air in the fuel rails
-plug wire going bad
-cap/rotoir wearing prematurely
-transmission failure

DRASTiK · 09-12-2002, 12:14 AM

fuel pump relay is a possibility. so is the TFI module.

sorry I can't be more help.

grant66 · 09-12-2002, 05:10 AM

I would first check your coil. If it is not your coil. I would check your TFI module. It is on your distributor. I had to take the distributor out of the car. You are going to need a special socket to get the module out of the distributor. I took my TFI module out and had Napa check it for me. Just my ten cents my two cents is free.

Mustang_289 · 09-12-2002, 06:41 AM

could also be the induction coil (pickup) in the distributor. We had similar problems replaced the TFI module initially than came back and replaced induction coil inside distributor. No problems since.

WADS56 · 09-12-2002, 06:58 AM

The exact same thing hapend to me a while back. My signal wire on my autometer tach was shorting out. Took me forever to find that one. I thought it was my ignition switch going bad utill I bumped my tach and the motor died.

93GTDIN · 09-12-2002, 01:38 PM

WADS56- tell me more about what happened to your car. The problem showed up again today except it was a little different. This time, on the highway or just cruising on the street, the car would start to jerk forward and backward violently as the rpms went erratic. I have tapped on the tach line for my remote starter, do you think that could be the issue? Also, when sitting at a stoplight, the car sometimes will just die. No sign of trying to keep the car alive, it just dies, as if I pulled the key out. Exactly like that in fact.

Anybody else have any idas?

bigblockcoupe · 09-12-2002, 02:13 PM

i would check the battery connections and make sure they are connected to the battery tightly and the positive is connected at the solenoid and the ground wire is grounded good it sounds almost like a loose battery cable or bad ground wire.

WADS56 · 09-12-2002, 02:16 PM

Do you have a aftermarket tach? Either way I think it is a ignition problem because of your simptoms.
I have my tach hooked up to the green wire on the coil. It was shorting out in the dash someware and the tack needle was going crazy. The engine would just sputter or die during normal driving or when I hit a bump. It was grounding the coil killing the spark and messing with the tach all at the same time.

DRASTiK · 09-12-2002, 03:37 PM

when your car dies, does it start right back up again?

93GTDIN · 09-12-2002, 07:48 PM

my problem was almost exactly that. One of my wires that connect the MSD inline had come almoast all the way out of place. Probably explains why the car did this some of the time. Either way it works now, thanks for everybodies help.

09-11-2002, 11:45 PM	#1
93GTDIN Registered Member Join Date: Jan 2001 Location: Live music capital of the world, TX Posts: 324	help-- I think my car is getting mad with me! I was driving on the highway today about 60 mph, when all of a sudden, my tach needle drops drastically to about 600 RPM, and for lack of a better description, bounces around. Eventually it popped back up to about 1700 rpm or so and ran fine for two minutes. DId the same thing again,and when the rpm's shot down, the engine seemed to miss horribly, maybe even backfire, but it was relatively quiet. Only think i'm confused about is why when the enginespeed dropped, the car didn't slow down. My first suspicion was ignition so I made sure all the wires were on pretty good. After inspecting the motor and deciding I couldn't see anything wrong, I drove it home and it didn't misbehave. Ten minutes after I arrived I took it for a ten minute (approx) drive and it did fine. So as of the current moment, I havent been able to reproduce the problem. Here are some possible problems I have conjured up, please help me add/dismiss theories. -air in the fuel rails -plug wire going bad -cap/rotoir wearing prematurely -transmission failure __________________ 96 Cobra - a bit too stock. 14.0 @ 101

09-12-2002, 12:14 AM	#2
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	fuel pump relay is a possibility. so is the TFI module. sorry I can't be more help. __________________ Dave 88 GT - 13.4@106 on street tires (2.2 60ft) My Stang RHC member #75 My stang is FOR SALE!!

09-12-2002, 05:10 AM	#3
grant66 Registered Member Join Date: Sep 2001 Location: Avon, CO, USA Posts: 63	coil or tfi I would first check your coil. If it is not your coil. I would check your TFI module. It is on your distributor. I had to take the distributor out of the car. You are going to need a special socket to get the module out of the distributor. I took my TFI module out and had Napa check it for me. Just my ten cents my two cents is free. __________________ If it isn't broke you are not trying.

09-12-2002, 06:58 AM	#5
WADS56 gear banger Join Date: Aug 2000 Location: CHICAGO Posts: 1,144	The exact same thing hapend to me a while back. My signal wire on my autometer tach was shorting out. Took me forever to find that one. I thought it was my ignition switch going bad utill I bumped my tach and the motor died. __________________ 79 Hatch: NA 347, Stage 2 Canfield Heads, Victor JR. Intake, Blueprinted Holley 750 HP, Solid Roller Cam, Shooting for 10's on motor 93 LX: Tremec, dual friction clutch, fms flywheel, Hedman shorties, O/R H-pipe Ricer hater's club member #49

09-12-2002, 01:38 PM	#6
93GTDIN Registered Member Join Date: Jan 2001 Location: Live music capital of the world, TX Posts: 324	WADS56- tell me more about what happened to your car. The problem showed up again today except it was a little different. This time, on the highway or just cruising on the street, the car would start to jerk forward and backward violently as the rpms went erratic. I have tapped on the tach line for my remote starter, do you think that could be the issue? Also, when sitting at a stoplight, the car sometimes will just die. No sign of trying to keep the car alive, it just dies, as if I pulled the key out. Exactly like that in fact. Anybody else have any idas? __________________ 96 Cobra - a bit too stock. 14.0 @ 101

09-12-2002, 06:41 AM	#4
Mustang_289 Registered Member Join Date: Sep 2001 Posts: 512	could also be the induction coil (pickup) in the distributor. We had similar problems replaced the TFI module initially than came back and replaced induction coil inside distributor. No problems since.

09-12-2002, 02:13 PM	#7
bigblockcoupe Registered Member Join Date: Aug 2002 Location: broken arrow Posts: 212	i would check the battery connections and make sure they are connected to the battery tightly and the positive is connected at the solenoid and the ground wire is grounded good it sounds almost like a loose battery cable or bad ground wire. __________________ Rice Haters Club member #68 '93 Cobra 10.20@135 '89 Gt Coupe 12.20@115

09-12-2002, 02:16 PM	#8
WADS56 gear banger Join Date: Aug 2000 Location: CHICAGO Posts: 1,144	Do you have a aftermarket tach? Either way I think it is a ignition problem because of your simptoms. I have my tach hooked up to the green wire on the coil. It was shorting out in the dash someware and the tack needle was going crazy. The engine would just sputter or die during normal driving or when I hit a bump. It was grounding the coil killing the spark and messing with the tach all at the same time. __________________ 79 Hatch: NA 347, Stage 2 Canfield Heads, Victor JR. Intake, Blueprinted Holley 750 HP, Solid Roller Cam, Shooting for 10's on motor 93 LX: Tremec, dual friction clutch, fms flywheel, Hedman shorties, O/R H-pipe Ricer hater's club member #49

09-12-2002, 03:37 PM	#9
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	when your car dies, does it start right back up again?

09-12-2002, 07:48 PM	#10
93GTDIN Registered Member Join Date: Jan 2001 Location: Live music capital of the world, TX Posts: 324	my problem was almost exactly that. One of my wires that connect the MSD inline had come almoast all the way out of place. Probably explains why the car did this some of the time. Either way it works now, thanks for everybodies help. __________________ 96 Cobra - a bit too stock. 14.0 @ 101