'95 5.0with elusive idle and running issues

Richard P

New Member
Joined
Nov 16, 2016
Messages
10
Reaction score
3
Group, you were so helpful leading me to the source of my odometer problems that I'll pose some other issues that has me scratching my head.
First let me erxplain that I'm the third owner of this low-mileage (75K), 5-speed, GT convertible, having bought it from a female nurse in Nov. 2016 who had owned it since 1997. It's bone stock, in very nice original condition, and has not been abused other than maybe sitting unused a lot in the 15 years before I bought it. Until recently when the EGR was disconnedted (see below) there has been no Check engine light on. Additionally, the ECM has been scanned several times with no codes being set.
Here's the issues that I've been struglling with since purchasing the car in 11/16:
1. Idle is unstable, especially when warm, but not very good even from a cold condition. It always starts fine with an idle of about 800 rpm but then after a few seconds the rpm drops to 400 or so and sometimes, particularly when warmed up, it will stall but is always easily restarted. Performance off-idle is better.
2. When accelerating and shifting through the gears, as the clutch is depressed, the rpm will jump briefly at least 200-300 rpm, then fall right back down. I've been very careful to make sure that my right foot is off the accelerator at the instance the clutch is depressed. I've also checked that the accelerator and speed control cables are not binding. Also, the reuturn spring at the throttle body is quite strong. So I beleive that ther's no mechanical issues in this system.
3. The car seems to miss or buck and jerk during low speed in town operation mostly when cold. I've recently heard this condition derscribed as trailer hitching. I can notice a slight similar condition at speeds up to about 55 mph.

Over the course of time I have replaced every vacuum line I could find, new upper intake manifold gasket, new Motorcraft IAC, new O2 sensors, complete tune-up with OEM spark plugs, wires and distributor cap and rotor, ignition module, and more. Recently, my mechanic suggested that the EGR valve be disconnected and plugged as a trial. That has been done and I do see some inprovement with Item 3 above. Otherwise, no difference with Items 1 and 2.

I apogize for the length of this message, but, for anyone who is still with me on this and who may have struggled with similar issues, I'd like to have any suggestions you may have to offer.

Thanks again,
Richard P.
Troy, Ohio
 
Last edited:

evilcw311

Most Evil Member!
SN95 Supporter
Joined
May 9, 2010
Messages
7,456
Reaction score
2,136
Location
Louisville, KY
Man......where to begin...... [emoji38]

Have you cleaned the maf?
Have you tested fuel pressure?
Has fuel system cleaner or any service on the injectors ever been done?
Disconnecting the egr can cause problems if not turned off in the tune with an aftermarket chip.
Have you metered the tps and did a reading from closed all the way to full open?
If you’ve done most of this have you tried doing a base idle reset??

Yes it’s a lot of questions but it’s all stuff to check and start with and any of them may show what’s going on.


Sent from my iPhone using Tapatalk
 
OP
OP
R

Richard P

New Member
Joined
Nov 16, 2016
Messages
10
Reaction score
3
Thanks for your response Mr. Moderator. The answer to most of your questions is yes. The only exceptions are noted following. I have not done anything with the injectors and I strongly doubt that anything was done to them before I took ownership. The ECM and all sensors, etc., are OEM stock (no tuner). I have not done a base idle reset not do I know what that is. Could you explain?

Thanks again,
Richard
 

evilcw311

Most Evil Member!
SN95 Supporter
Joined
May 9, 2010
Messages
7,456
Reaction score
2,136
Location
Louisville, KY
I’d have to do a little searching. It’s been a while since I had to do it. When I get time tonight I can look.

Otherwise do a quick research on the net for the 5.0 base idle reset for 94-95.


Sent from my iPhone using Tapatalk
 

white95

Apex Junky
Admin
Joined
Dec 30, 2007
Messages
20,370
Reaction score
8,248
Location
Prairieville, LA
^ This.. The PIP sensor in the distributor is notorious for failing in the 94-95.

Another item to address is cleaning the IAC valve out.
 

evilcw311

Most Evil Member!
SN95 Supporter
Joined
May 9, 2010
Messages
7,456
Reaction score
2,136
Location
Louisville, KY
^ This.. The PIP sensor in the distributor is notorious for failing in the 94-95.

Another item to address is cleaning the IAC valve out.

Has new motorcraft iac.




Sent from my iPhone using Tapatalk
 

ttocs

Post Whore
Joined
Oct 9, 2009
Messages
32,205
Reaction score
5,493
Location
Evansville Indiana
This almost sounds like the same general problem I was having with my TPS sensor. When the car would get up to temp the tps would start to show anywhere from 2-5% throttle when I was not touching anything. It was a small problem and you would only see it if you were monitoring the tps data when it was hot. I thought I had it down to the tps sensor after tapping on it with the handle of my screwdriver(technical taps) and watching it jump around. I put a new one on and it did the exact same thing. I finally diagnosed it down to the harness for the tps. When it got hot, it did not make as good of contact and that would change the voltage it was reading and the computer would think I was giving it gas. Tap around the IAC, TPS and all the other little crap with your screwdriver as it could be similar. If doing that shows any difference to how it runs then try giggling the harnesses that connect to them to see if it does the same.
 
OP
OP
R

Richard P

New Member
Joined
Nov 16, 2016
Messages
10
Reaction score
3
Hello Group,
I owe the group an update on progress I've recently achieved addressing the issues covered in my posting of August 10th. Since then I've replaced the EGR valve which helped a little. I was strongly considering replacing the injectors but decided first to re-run the ECM codes even though the the CEL has never been on. One code showed up-it was related to a fuel pump relay failure (don't remember the actual code number). I discounted this information but, before proceeding to purchase new injectors decided to focus on the timing and distributor. The timing may have been off a bit, but while having the SPOUT connector removed, I also disconnected the PIP sensor wiring to the distributor and thoroughly sprayed contact cleaner in both halves of each of these two connectors. Almost miraculously, after these connectors were reconnected the issues have almost entirely disappeared. The car, for the first time since I bought it three years ago is now, and has been for about six weeks, idling at a good, stable rate of about 700 rpm and, otherwise, runs fine. The only issue remaining is a 'jump' in rpm when I'm shifting up through the gears. From what I've read on-line, this may have been designed into engine operation by Ford. Even this issue doesn't seem as bad as before I cleaned the connectors but still noticeable and annoying.

I'm about ready to store the car for the winter but am planning to install a new aftermarket distributor on it. Then, over the winter, I plan to rebuild the Ford distributor with a new Ford PIP sensor. Maybe this will help even more. I don't know.

FYI, I also have recently purchased a new 'toy', a 2007 Saleen Parnelli Jones Edition Mustang (grabber orange). This is the dream car I've always wanted but couldn't afford till now. It's basically new with only 1400 miles on it, all original.

Thanks again for all the help you guys have been. I'll post again when I have more to report (probably not until next spring when both of these cars come out of storage). Have a good winter.

R. Pittenger
Troy, Ohio
 
OP
OP
R

Richard P

New Member
Joined
Nov 16, 2016
Messages
10
Reaction score
3
PJ Mustang-101919 001.JPG PJ Mustang-101919 032.JPG I certainly don't want to be banned from the forum so here's a couple photos of the 'new to me' Parnelli Jones Saleen Mustang. It's all original, untouched and came to me with a number of 'extras' as it's first owner was Saleen's VP of Sales at the time.
Shown in the second photo, taken on the day we brought the PJ home is my 12 year old grandson (budding car enthusiast) and the '95 GT vert, subject of the original postings.
 
Last edited:
OP
OP
R

Richard P

New Member
Joined
Nov 16, 2016
Messages
10
Reaction score
3
I'm surprised that no one commented on the fix I shared with the group in my last post concerning the significant improvements achieved in idle condition, etc, simply from cleaning the contacts in two ignition system connectors. Is anyone out there?
 

evilcw311

Most Evil Member!
SN95 Supporter
Joined
May 9, 2010
Messages
7,456
Reaction score
2,136
Location
Louisville, KY
I'm surprised that no one commented on the fix I shared with the group in my last post concerning the significant improvements achieved in idle condition, etc, simply from cleaning the contacts in two ignition system connectors. Is anyone out there?

I hadn’t seen anything yet. I’ve been crazy busy lately so I’ve barely glanced over a lot.

It’s crazy what a little cleaning of electrical connections can do.


Sent from my iPhone using Tapatalk
 

Latest posts

Forum statistics

Threads
77,354
Messages
1,499,935
Members
14,844
Latest member
MWTULLY22

Members online

Top