I recently put a new clutch kit, slave cylinder, clutch master cylinder, and hydraulic lines in my 94 F150 with a 300 I6 and a 5 speed mazda transmission and about 1000 miles later (now) I'm feeling a "chugging" feeling when I accelerate lightly shortly after shifting. I also am getting a misfire now that is more pronounced than before which I think may be the culprit, but I haven't been able to pinpoint it yet partly due to the truck having the 'dinosaur' OBD1 that doesn't tell you anything...
Half of the time when it does start chugging or lacking power the SES light will come on for a little while and then turn off shortly afterward when it feels like it clears itself out. It seems to me like it only happens when the engine is mostly warmed up or fully warmed up.
I replaced the plugs, wires, cap and rotor and set the ignition timing, but I wasn't positive of the position due to the difficulty in seeing the timing mark on the crank on the 300 and I did adjust it quite a bit and it seemed like it was running better but it is warming up in this region which lead me to suspect a timing issue or that I didn't adjust it properly.
I used autolite plugs when I tuned it up which are the OEM manufacturer of motorcraft plugs but I only used the regular copper plugs which I haven't had much luck with for lasting more than about 10,000 miles in the old fords without starting to burn up.
I also started thinking I had a bad coil because when I wash it, even when I leave it running it starts misfiring really bad if I even only get a little water on the coil and the fact that it only misses when it is warm made me suspect the coil as well, but I also fear it could be an intake manifold gasket due to the misfire when warm as well...
Any suggestions or ideas????

 

Does it only misfire in gear only, or will it do it in neutral as well?

Any codes at all being feed from the computer?

When you adjusted the timing, did you remove the spout connector?

 

it misfires when warm at idle, and it surges when accelerating when its warm i already clearly stated all of that. and there's no way to retrieve codes from an obd1 system that aren't currently in the system because the codes aren't stored and aren't a hard code

 

Have you tried to check for codes? I read your post and did not see where you have checked for any. Just that it is the OBD 1 or EEC IV system. You stated that if it is not a "hard" code it will not show up. That is correct. However you should have continuious codes stored in the system. It will not pinpoint the exact cylinder, but it might give you a place to start looking for the problem.

 

Yeppers. So did you get any codes?

Did you remove the Spout for adjusting the timing?

Are you going to get snappy again?

 

okay today i got it good and hot and sprayed down the intake with brake cleaner and got a stumble when i hit the number 1 intake port so i'm pretty sure i need to do the intake manifold gasket. i also had o2 sensor codes stored in the pcm, but i'm thinking that has something to do with the leak. so any suggestions or tips on replacing the gaskets?

 

It is possible the O2 codes were caused by a leaking intake gasket. But, the code numbers will help us help you more. Even though it is the EEC IV system, it will give us something to research to help you. There is about 17 different cpdes that could be considered O2 codes in the 3 digit format. There are 7 codes in the 2 digit format. You can go to www.autozone.com and get free repair information to give you specs. It is the same information as in Allsdata DIY. Good luclk and let us kinow what the codes were.

 

Once the bad gasket is replaced, you could clear the codes and run it for a while to see if they come back. If any come back, you'll know that there is a separate issue at hand.

 

I meant any heads up on replacing the intake/exhaust manifold gasket? Any tricks to getting the pipes separated from the exhaust manifolds without cutting them apart or for getting the bolts and studs out of the intake and exhaust? Alldata only gives a basic disassembly procedure, but it gives an excellent and concise reassembly though.

 

Once everything is appart, you may need a puddy knife to scrape off parts of the old gasket and rtv seal. Use a PLASTIC one so it doesn't scratch the metal. When putting back together, you should have some RTV seal ready just in case.

Removing the exhaust manifold is straight forward. Unbolt and scrape off old gasket with a plastic puddy knife. When putting them back on, you will notice that the replacement gaskets ususally have hooks on the ends instead of holes. This is so you can put the outer two bolts through the manifold and thread them a bit into the heads. Then, since the manifold is on loosely, you can put the gasket in place. After that you can thread the rest of the bolts in. After that, tighten them up and you are all set. You should double check the tightness of the exhaust manifold bolts after a few days of use; they will probably need to be tightened again.

Good luck.