Idles fine, Rev engine high manually, engine comes down and eventually dies

DustinMcClintock

New Member
Sep 14, 2020
2
0
1
26
Springfield
I am having an issue with my 1989 Ford Mustang with a 2.3L 4 cylinder.

Car sat for about two years and is a convertible model (don't know if that matters but giving all information i know), i drug the car out this weekend and worked on getting it running. I believe it had roughly a quarter of a tank of gas that has sat for 2 years, I'm here to try and get some help before i sell it.
I got the car running by replacing the starter solenoid, starter itself, new battery and ran sea-foam and octane booster through the engine. I also ran a little bit of sea-foam through the oil and let the car idle for two hours before changing the oil and putting in new oil and oil filter. The problem i am having is weird and never experienced anything like this. The car will idle with no problems, starts up and can sit in idle all day (as long as you add gas), but when i put the mustang in Neutral and rev the engine high it comes down slowly and then sputters and eventually dies, it doesn't have a problem driving at a slow speed 25 or so when not revved, as soon as you rev the engine not sure what I'm hitting as the tachometer doesn't work fully but seems to be in the 4k or 5k range then sputters and dies, but will start right back up and idle no problem. I was told two things and want to verify this: One person said bad fuel and to drain tank and start fresh, the other said possibly the Throttle Position Sensor, just looking for more input on what it could be. I have another issue with Overdrive but i don't think the two are related, overdrive works when the car is cold and will shift into it, but you get into the gear one time and once the car warms up it wont go back into overdrive. Any help would be much appreciated and I'm sure i will be back when working on one of my other mustangs.
 
  • Sponsors(?)


junkyardwarrior

5 Year Member
Jan 10, 2011
307
72
48
typically when they sit a while, the fuel goes bad.

When the fuel goes bad, a lot of times it gells up the fuel pump, sock, fuel filter, sometimes the lines, the injector screens as well. Most of the time you can smell it, old fuel stinks to high heaven.

Ideally you'd need a fuel pressure gauge to see what's going on but I suspect that once a load is placed on the engine (accelerating) you'll likely find that fuel pressure is dropping off.

The high idle probably ain't because of the fuel; likely a separate issue. Pull the codes and see what you get. I'm thinking TPS as well. Possible vacuum leak.
 
Thread starter Similar threads Forum Replies Date
D Idles Fine, Rev engine High Manually, engine comes down and dies. 2.3L (N/A & Turbo) Tech 0
L HELP: drives fine for 15 min, then wont rev up or idle nicely SN95 4.6L Mustang Tech 3
1992 5.Slow GT B303 cam swap on my 92 GT now running rich and falls on its face, idles fine tho. Fox 5.0 Mustang Tech 6
1995COBRA 95 Cobra starts right up and idles fine at first, but then after about 2 minutes, I try and restart and it does not hold an idle. 1994 - 1995 Specific Tech 12
S Engine 95 Gt Fine At Idle Overheats At Speed 1994 - 1995 Specific Tech 4
96nickSn95 Runs Fine But Idles Low When In Drive SN95 4.6L Mustang Tech 7
Johhny J Car Idles Fine Then Dies Fox 5.0 Mustang Tech 1
f8tlfiveo Was Idling Fine..... Fox 5.0 Mustang Tech 3
V8_Kind_Of_Guy Car Idles Fine, Give It Gas And Wants To Die Fox 5.0 Mustang Tech 11
M Idle Drops Immediately After Start, Then Fine 1994 - 1995 Specific Tech 6
B 98 Gt Starts Fine Then Shuts Off While Driving/idling SN95 4.6L Mustang Tech 20
B Engine Engine Starts, Idles Fine But When I Push The Peddle It Dies. SN95 4.6L Mustang Tech 4
PlatinumDevil Car wouldn't idle, clunk, running fine... SN95 4.6L Mustang Tech 0
Crs Car starts, idles fine, dies when put in gear. Classic Mustang Specific Tech 3
D 351 idles fine dies when in gear Classic Mustang Specific Tech 4
Methodical Car idles fine until..... see pics inside...help 1994 - 1995 Specific Tech 20
6 5.0 missing at idle, but runs fine otherwise Fox 5.0 Mustang Tech 1
Pokageek Car idles fine but cuts out half the time at a stop. Ideas? 1994 - 1995 Specific Tech 18
mustanggt94 TWEECER NEWBIE HERE! Need help fine tuning: Idle & Bucking problem 1994 - 1995 Specific Tech 11
G 3.8/auto - ZERO codes - terrible idle - not driveable - backfires SN95 V6 Mustang Tech 0
J Engine Help with cold starts and cold idle Fox 5.0 Mustang Tech 2
M Progress Thread 2014 Automatic idle/accelaration Issues 2005 - 2014 S-197 Mustang -General/Talk- 0
7991LXnSHO Drivetrain New hanging idle problem Fox 5.0 Mustang Tech 7
SemperFIGOD Idle kpa Digital Self-tuning Forum 9
C Engine Higher idle then normal 1994 - 1995 Specific Tech 8
A Hunting idle 4.6 2v with stage one cam Digital Self-tuning Forum 0
92j3ieje8 Car turns off and idles low. 1996 - 2004 SN95 Mustang -General/Talk- 0
1 2005 V6 shudder at idle in gear 2005 - 2009 Specific Tech 6
danielhv Bad Idle Air Control Valve? Digital Self-tuning Forum 9
J Idle Adjustment Issues 2.3 Turbo fuel injectedto 2.3L (N/A & Turbo) Tech 16
0 4.6 2v SOHC 2k rpm Idle, help reading engine data SN95 4.6L Mustang Tech 2
I Microsquirt idle after clutch engagement Digital Self-tuning Forum 1
africansnowowl Engine Update: Another rough idle thread Fox 5.0 Mustang Tech 17
J Looking for 2005 GT OBD2 idle sensor reading 2005 - 2014 S-197 Mustang -General/Talk- 2
J Engine New Manifold nightmare idle and stall 2005 - 2009 Specific Tech 4
C 2013 GT low oil pressure at low RPMs or idle 2010 - 2014 Specific Tech 0
R Engine Remove the Idiot from the equation. Idle/hesitation issue. Fox 5.0 Mustang Tech 3
C 2014 Mustang Gt/Cs Idle and dying issue 2010 - 2014 Specific Tech 2
T MS3 AC Idle Up Settings Digital Self-tuning Forum 1
93silverlx50 Engine Car in limp mode, fuel spitting out of tailpipes, missing rough idle Fox 5.0 Mustang Tech 9
markinms Engine Should Auto Trans Be in Drive When Setting Base Idle Fox 5.0 Mustang Tech 7
R Fuel Throttle body idle screw 1994 - 1995 Specific Tech 2
darryl paarman A/C idle up control- Low input or High. ? Digital Self-tuning Forum 2
C Engine Gray smoke from exhaust. Smells like gas. Fox 5.0 Mustang Tech 15
lamrith New MSPnP2 in 94 Mustang, need help getting stable idle once warmed up. Digital Self-tuning Forum 1
J Idle issue still!! Replaced several parts.. looking for more ideas!! Fox 5.0 Mustang Tech 12
G 1998 3.8L V6 overheating at idle, gauge doesn’t go up. SN95 V6 Mustang Tech 3
bmgstang Need help with tune high idle Digital Self-tuning Forum 7
S Another Idle surge post with microsquirt Digital Self-tuning Forum 5
H Engine Tach goes to zero,engine goes to idle on 87 GT Fox 5.0 Mustang Tech 10
Similar threads