I have a 96 with 120,000 miles, runs great but on windy days has trouble pulling it self down the road. Suspecting exhaust. Anybody have any ideas on how to check for restricted exhaust? Any help would be appreciated, thanks.

 

Been there. Sometimes I had a hard time maintaining 65 mph.

A good tune up and air filter will hep. Check your timing after verifying tdc and marking with some white out.
The first thing I tried after the tu was the exhaust. I still have both cats but 2 1/2" from the rear cat back thru a magnaflow. Be careful here because the outlet on the rear of the cat is stepped and to get back to the 2 1/2" part requires cutting the flange pretty close to the cat. The shop didn't want to do it because they said it was too hard to get to. I went all the way to the rear side but shortly am going to change it to foward of the passengers tire. Just too many ugly bends going all the way back. I don't know if this enough to cure your problem but it will make an improvement.

 

How is your MPG cause i have a 96 auto and it pulls down the road fine. I would guess it would be a tune up issue not an exhaust issue.

 

On industrial equipment is used a 1/8" NPT connection at exhaust pipe, close to engine. It is connected to a pressure gauge calibrated for In/Hg. Using this gauge at your normal driving or climbing will give you an idea on how free is your exhaust.

I had solded that connection to my F150 just side to O2 sensor.

 

I have done a tune up minus timing check, I'll try that this weekend. I have pulled the muffler off it helped a bit but sounds like crap, been talking to muffler shops and they check their cats with a pressure gage in 02 sensor bung or with heat gun. They say the temp should be hotter coming out then it was going in. I tried my truck with the gun and the front cat comes out 100 degrees hotter and the second cat is coming out about 165 degrees colder. Maybe I found my problem. The muffler shop sugested just pull the last cat or replace both with one. What do you think would be best? I guess I better find a new muffer also.

 

I was getting about 27 if I drive it right but lately its been about 18. What does your auto rev at cruising down the highway at 65?

 

Sounds like you have found the problem so now what is the best solution? I have tried the partial fix thing and it has shown a definite improvement but I'm sure it could be better. I had planned to go back and do it right this weekend but looks like the "Honey Do" thing has put me on hold another week. From my experience I would suggest doing what the muffler shop suggested and go with one high flow cat. Do it complete and right the first time and you won't be like me and have to go back and do it again.
Keep us posted on what you do and the results. It should help answer a lot of "What ifs and Maybes". Might even save somebody else the trouble of having to do it twice

 

Just got back from the exhaust shop and what a world of differance, it's like a new truck. They done a pressure test to check for back pressure, and showed the rear cat at fault. I had them just remove the rear cat put a chunk of pipe in and a new hi flow muffler. I tried to check my timming the other day but I didn't know how to disconnect the advance. Any body know?

 

Have a look side to your distributor, there is a gray plug, just disconect it and your timing can be checked now.

Don't work on plug while engine is on, doit key off.

 

easy way to check for exhaust restriction is to hook up vacume gage at the intake.remove one of the caps and you should have aprox 16-20in vacume.now stomp down on throttle. gage should drop to zero then back to 16-20in.if gage doesnt move and the truck sounds like jet then exhaust is plugged.

 

Thanks for the help!!!!!!