misfire

Need help diagnosing whats wrong with my 03. No shop in my area (south FL) will touch the car because its “too old”. All new top end (original cylinder heads failed leak down test and had bad spark plug repairs). Here is what has been changed…ported stock 99 casting heads with SI valves...

Have 93 fox with new spark plugs,new coil, cleaned maf,new air filter. The car cruising run good but at wot the car bog and hesitate exactly at 3k rpm, sometimes even don’t respond to throttle and die but turn it on and runs. Today it give code 11,63,33.

Hello all, I am in the process of recording datalogs for my tuner to get my Mach 1 dialed in. The base tune is dialed in according to my tuner, so he requested some 3rd gear 2,000 to 5,000 rpm pulls. On the first pull at WOT it felt like I hit the rev limiter at ~5,000 rpm. I am not sure if it...

I have a ‘65 coupe with a ‘91 5.0 that has an edelbrock carb and pertronix distributor and coil. It’s been running fine the last couple years from when I did the engine swap. Recently it started getting a small random miss, and under harder acceleration it seems like Almost the entire engine is...

Hey, hope everyone is doing well. Got a couple questions that I've been trying to get answers for for awhile now. I own a 5spd '04 GT that I bought around 5 months ago. My Mustang does not have cats or a check engine light. Are there any codes that are thrown up that could indicate that my...

2002 Mustang 3.8 Automatic 198,564 Miles Current mods: MAC OffRoad H-Pipe, K&N CAI, MSD Wires I got a code for misfire on cylinder 5 (P0305) a month after rebuilding the upper end of the engine (had a blown head gasket). The car ran extremely smooth and got great gas mileage before the problem...

1987 5.0 Manual, timing chain broke after I finally had it running well Rebuilt with an upgraded cam. Original heads with a valve kit. Gear driven timing. Newer explorer intake Harness and A9L computer out of an 89 for the MAF conversion. EGR deleted since it has a newer explorer intake. All...

Hey all, I searched around but didn't see a thread dedicated to this specific topic; please link to one if I'm wrong! I've had a #6 misfire on my '03 GT first about a year ago and thought I had fixed the problem by swapping the ignition coil. It's been fine since then until about a week ago...

Hello, I am running out of ideas trying to solve a stubborn misfire. I have a rebuilt carburated 302 running a light cam, but is otherwise stock. Problem is I am getting a fairly severe misfire at 0-25% throttle. Only misses while under load, no miss out of gear. This problem started a few days...

Well after hours and hours of following guides and videos and blah blah blah.. I finally found the issue of idle surge, hesitation under throttle, stumbling, bad mileage.. etc. Incorrect spark plug gap.. and since people are going to ask they were gaped at .035 not .055 and here is the reason...

my fox was running fine up until a week ago. now when i floor it it doesnt pull hard, kind of hiccups. im also starting to hear weird pops when i let off the gas which i think is misfire. the idle is good for the most part but just yesterday i noticed it drop a little 2-3 times over the period...

So not that long ago, I ran the tank almost empty. I did not run out of fuel but I was with 6 miles. I have a 2005 Mustang GT and it’s slightly modified, so 6 miles is probably closer to 2-3 miles. Anyway, since that day, I’ve been having a horrible stutter on acceleration. It does happen at...

Hi, so I just recently got my car street tuned (306, Cam, GT40 top end, On3 Turbo kit) and the car developed a misfire. During the tune the car was running fine, no misses or anything, but on my way home, I did a pull going on the freeway and it misfired on the top end under wide open throttle...

Hey everyone, just bought back my first car. It’s a 2004 mustang 3.8 5speed. The owner I sold it to just rebuilt the transmission back in June and just swapped in a new motor w 80k miles last week. The car has a few strange issues though, the first was a random misfire on startup (first 1000...

Have a 93 lx that I bought a little over a month ago. Had some issues, and it sat for a while. New to fox bodies and still new to this car In general. So some insight from experience can help. Before I describe my current issue, I’m going to give some history on the things that I have done to...

I've been having this problem ever since I bought this mustang I changed few stuff, but I still have it. Hopefully you guys can help. I have a mustang 2002 3.8L coupe and it has the weirdest misfires at times. In the morning when the engine is cold It starts perfectly and It has no problems what...

hello all, I'm new to the whole tuning scene and have been battling this problem for a couple weeks now. I have been asking around on the net for some help, but seems a lot of the sites are more about bashing and criticizing me for not knowing instead of helping.. One fellow i did run into that...

Hello! Ive just had a problem with my stang. I didn’t know where else to go, or look so hope this is the right place! Last night heading home I bottomed out going too fast in my neighborhood, and it was loud! Anyway I didn’t notice any problems so just parked and went to bed. Well the next...

So, I did the intake manifold swap for my car. Went from a crappy Dorman intake for a non PI motor and put on the Ford Racing Performance Intake manifold. It was actually used and off of a 2002 Grand Marquis but same crap right. I now have a misfire. Yesterday she ran like a top! Now...

Hey guys I've got a serious ignition issue and at this point im just looking for other opinions 1995 Mustang GT 5.0 Bored and Stroked to 347, 5 Speed, Convertible California Car. So this car has been an ongoing project, did the engine and have been having serious ignition gremlins since...