5.0L (1979-1995) MustangTechnical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.
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Hey guys heres another fun thread.
So as you all already know I currently own a 1988 mustang 5.0 lx. I bought the car back in november and I've had multiple issues. I currently have a misfiring issue so I was told to replace multiple things. I would get a misfiring/popping sound from my vehicle under a load and would feel like I am losing power until the car would catch up and speed up the misfiring ended. I replaced the fuel filter, sparkplugs (motorcraft gapped at .052), ignition wires (autolites), MSD Cap and rotor, MSD Ignition coil, Oil & filter change, Did a 3g alternator upgrade to a 130 amp alternator(kit bought from latemodelrestorations.com) with a bigger gauge wire that goes from the alternator to the ignition system, cleaned out the Iacv(looks brand new and had no carb build up in it at all so I believe that the previous owner knew about the issue), tested the TPS and it was at a .97 so it checked out good, I replaced the tfi ignition module(made no difference) so I was told I couldve been the pip sensor in the distributor. I just replaced the distributor about 2 weeks ago and when I did I made sure the #1 cylinder was top dead center and made sure the rotor was pointed toward the number 1 cylinder/sparkplug and installed the distributor. Then my neighbor(builds cars for atco raceway here in sj) used a timing light and set my timing to 12 degrees. After the new distributor (the brand is Tough One?) was installed I noticed that the car actually now bucks/jerks forward if i stay at a steady/constant speed. For example if I drive 25 mph for a while it'll buck/jerk forward a couple of times until I increase acceleration. Although this problem doesnt occur if I accelerate or am sitting at a light in neutral. After all of that work, the misfiring issue is still present, although it did seem to go away for a day or two after the distributor install. About a week ago I installed 6 new speakers and a new headunit correctly, and last night when I turned on my headlights, I noticed another problem now. The headlights were flickering and so was the lite up dashboard. The battery gauge on the dashboard itself was bouncing up and down as well(not giant bouncing but bouncing up and down as fast as the flickering). I've never had this issue before and it hasnt gone away since last night. It cant be the aftermarket headunit or speakers because this problem just began to happen and theyve been in for a week already. The negative and positive cables arent loose either so what could be the problem? The car still misfires/pops and bucks/ jerks forward at a constant speed and now I have this issue on top of it. I am really about to bash my head through a wall... I've only had the car almost 3 months now... and it didnt seem to have these issues the first few weeks i've had it... please help me...? :banghead:
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When you tested the TPS, did you do a sweep test to look for dips/spikes in voltage readings? And you checked all your grounds?
No spikes/dips in readings it was steady just going from .96 to .97 I believe and I dont know all of my ground locations? I see one near each headlight, one near the battery from the negative cable and one on the drivers side firewall to the engine.
Also i just went to advanced auto to get a system check. The battery test: Good Battery. Voltage: 13.02v, Measured: 654 CCA, Rated: 540 CCA, Temperature 59F "Battery Meets or Exceeds Required Standards". The Starter test: Cranking Normal: Voltage 10.52V, Amps: 0.0A, Time: 1.12S. The Charging System Test: Results: No Problems, No Loads: 14.99V, Loaded: 14.64V, Ripple: 88mV. Charging system output test normal.
Just used my actron obd1 code scanner. On the KOEO test I got system pass. On KOER test however, I got code 41. Code 41: Exhaust Gas Oxygen (EGO) sensor: Voltage Signal always "Lean" (low value) - does not switch. This wouldnt have anything to do with my whole bucking/ jerking forward, dashboard and head light flickering and battery gauge jumping issue would it?...
Cruising speed misfires/bucks are usually a result of a vacuum leak induced by the EGR system. O2 reading lean would seem to concur.
Well I went to put a 4 gauge wire from where the negative battery cable mounts to on the engine to the ground next to the battery, and It didnt reach so I took it back but they didnt have a longer wire. Instead I bought a 4 gauge negative battery cable(same as the original) the only bad thing about it is that its 78 inches long which is too long causing me to ziptie and electrical tape a bunch of it together.. anyway I put that on and the car started right up and the battery gauge stopped bouncing and the dash and headlights didnt flicker the rest of the day. Today however I started my car and those issues are back... what do I do now? I had everything tested under load and posted the results above^ so its not the alternator... Maybe the battery then? do I need a bigger and better battery? I have a cheaper one its "pro start"... as for the bucking, my car didnt start doing that at a constant speed until I installed the new distributor...? About the egr what does that mean>?
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