Been going thru alot since redoing my intake. went with an edelbrock performer upper and lower, edelbrock 65mm tb and spacer, accel 19 lb fuel injectors,bbk fuel pressure regulator, motorcraft egr and iac valve, pro-m 75mm maf, new h-pipe, new cats, new o2 sensors and harness (had code 41/91 they are gone now problem still persists),replaced plugs, wires are less than 5 years old, new rotor on dist less than 5 years old but original dist. I try and drive it and get the popping out of what sounds like the exhaust and very poor acceleration and bucking. a week ago this only happened when the car warmed up and the check engine light came on giving me the 41/91 code. fixed the sensors,cleared the codes. but now its all the time , cold or hot if i try and move it the car just bucks like a bronco and pops out the exhaust. i can avoid this by driving it like an idiot and keeping the rpm high at like 2-3k while im letting out the clutch, once i get going it doesnt seem to pop or buck unless im at low rpm, but the power is for sure lacking thru the entire rpm band. All this is accompanied by a rough start after sitting for a few hours, i go to turn it on and it just turns over. i do it a couple times,like 2 or 3 key turns for about 3 seconds each, and eventually it roars to life to 1500-2000 rpm like you would expect then drops down to a low lumpy 650 idle instead of 900ish like it should and slowly gets better and better over 1-2 mins eventually leveling out fine i can shut it off and start it back up with no issues, its just when it sits for a period of time. My next guess, and thats all it would be, is the fuel pump is no good. Check valve is blown so the lines dont hold fuel which would explain why it wont start after sitting? popping and bucking because of lack of fuel? i put the new MAF sensor in today and it seemed like it made the problem way worse, like almost undrivable, is the car demanding more fuel because of the new maf and the pump cant keep up or did the problem just get worse on it own and its a coincidence that i put the new maf in around that time? im at a loss here. since dealing with this ive replaced the 02 sensors and harness, cats, set base idle, bought new iac valve, played with timing from 10-14 nothing helped.
Engine 89 lx 5.0 popping/surging under load but idles okay.
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Why guess and throw parts time and money at a problem; diagnose!!!
Start by dumping the computer codes- all 3 sets of codes, key on, engine off, key on engine on, key on continuous .
Dump codes sticky
Look at the top of the 5.0 Tech forum where the sticky threads are posted. One of them is how to dump the computer codes. Codes may be present even if the CEL (Check Engine Light) isn’t on. You don’t need a code reader or scanner – all you need is a paper clip, or if your lady friend has a hair pin, that will do the job.
I highly suggest that you read it and follow the instructions to dump the codes. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/
Start by dumping the computer codes- all 3 sets of codes, key on, engine off, key on engine on, key on continuous .
Dump codes sticky
Look at the top of the 5.0 Tech forum where the sticky threads are posted. One of them is how to dump the computer codes. Codes may be present even if the CEL (Check Engine Light) isn’t on. You don’t need a code reader or scanner – all you need is a paper clip, or if your lady friend has a hair pin, that will do the job.
I highly suggest that you read it and follow the instructions to dump the codes. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/
Ive pulled codes. Koeo nothing aside from all clear. Koer gave me 41 91 and i addressed that by putting new cats and 02 sensors with a new hpipe. Codes are gone problem persists. I guess i can try and pull again but all i ever got was 41 91 aside from the 11. I had egr codes but fixed those. I know it seems like im throwing money at it but these are all things i would have needes to replace anyways. Practically everything is stock with 240xxx aside from what ive replaced. Car has been in the family since 2000 so i know almost all the history and the time i didnt have it i have documented up to about 90k miles.
The car ran, idk about perfect but it ran before i started replacing parts with the intake. I tried to stay near stock with the new parts, 19 lb injectors 65 tb etc to avoid pissing off the ecu. But it looks like i did a good job of that anyways. Not going for a drag car just restoring my dads fox for a spirited drive on the weekends and such.
You don't really 'pissoff' the ecu, all it does is try to control the chaos, sensors tell the ecu things, the ecu controls events based on this info from the sensors. When a sensor like the 02's put out a code 41/91 that does not necessarily mean they are bad, further testing must be done to find out why they read lean, all this is spelled out in the 5.0 tech/how to forum, look for 'surging idle checklist'. You will likely find a vacuum leak someplace, go through the checklist step by step and you should be able to resolve your problem without randomly replacing stuff and hoping you've fixed it.
The idle is fine tho, aside from the car giving me trouble on the 1st start of the day once i get it going for 2 mins it idles at 800-900 fine. Its just when i put the engine under load that i get the loss of power and popping. A week ago i could fire the car up cold and drive it for 15-20 mins like it was fine, power wasnt all there but no popping and bucking until 20 mins or so, then the cel would come on with the 41/91 at the same time it starts running like 
. Not looking for a definite answer just a push in a right direction. I dont mind replacing all this old on my way either. At the very least i got a new part out of it, and at this point how many more things could possibly cause this?
. Not looking for a definite answer just a push in a right direction. I dont mind replacing all this old on my way either. At the very least i got a new part out of it, and at this point how many more things could possibly cause this?Its driving me nuts because its coming and going. Like i said a week ago i could drive the car with the stock h pipe and cats 240k miles 1 o2 sensor ripped out 1 plugged into an oil and anntifreeze saturated harness. Even still i could rip down the road and chirp 2nd gear. Now it wont even go 10 ft without seeming like the engine is gonna hurt itself so im thinking i have an intermittent fuel clogging issue. Is that logical?
The logical thing to do is go through the checklist and find/fix the problem(s).
This list was put together by people that have a ton of experience diagnosing and fixing these cars. Believe me, it helped me fix my junk, if I can do it so can you.
This list was put together by people that have a ton of experience diagnosing and fixing these cars. Believe me, it helped me fix my junk, if I can do it so can you.
I am the guy who wrote the checklist; it is specifically designed to start with the high failure rate items at the top of the list. Start at the top of the checklist and work your way down it sequentially, one item at a time. Do not pick and choose, do not skip around, do not pass Go and collect $200. Do all the items because the one you skip may be the very thing that leads you to find the problem
I want it to be my solution for sure i appriciate all the time you and the guys on here put into it. Its just that my idle is fine. Once i get the car started after turning it over a couple times(takes a few attempts) it idles steady at 900. I can sit in neutral and rev the engine with no issues at all, my problem is when i go to accelerate i get the popping. Its almost like its electrical arcing cause its very rapid. Im starting to look at the distributor funny now. But this weekend im gonna go thru that list again before i drop 400 on a new dist and coil.
No need to spend $400, the stock distributor and coil will work great for all N/A applications.
Stock distributor, stock coil. I've seen a stock distributor polished up look'n pretty but it's a lot of work, I think I have a msd distributor but it's been so long I'm not sure any more, got it on sale, been good for over thirty thousand miles and I don't cut this rag much slack, I guess I should compile a list of what I've updated over the years. A stock distributor is the smart way to go.
I wouldn't waste my money. MSD as a whole has a low quality and high failure rate reputation.
"As soon as you crank your Mustang, if there is a high-pitched shriek, the distributor cap and rotor need to be cleaned/replaced or the entire distributor needs to be replaced" i just read this on the Late model restoration site. I have exactly that. Once i do manage to get it started it screeches like a bird really quick. Is this accurate?
When you guys say stock dist you mean a remanufactured one? Like this https://www.americanmuscle.com/distributor-8693.html
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