Skip to main content ↑ ↓
Topic: 302 Running like . Still can't find issue (Read 3108 times) previous topic - next topic

302 Running like . Still can't find issue

Its an 88 with a 5.0

So it's been riding like . In idle it misfire and burn richly. Un burned gas (black/grey smoke out exhaust non stop) When you give it gas while in park, it'll still function but misfire causing entire car to shake. THen once you let off the gas it dies. I've had a few mechanics look at it and nobody can figure it out. This is what i've done to try to troubleshoot the  thing:

-New spark plugs
-New Spark plug wires
-New distributor cap/rotor
-New MAP/BAP sensor
-New MAF sensor
-New ignition coil
-New o2 sensors
-New EGR spacer
-New fuel pressure regulator
-New "idler"
-New TPS (adjusted to 98)
-New gaskets on Upper to lower intake manifold
-I've checked all vacuum lines and made sure they're connected properly and going to the right place
-We've double checked firing order
-Checked manifold with vacuum gauge
-Unbolted exhaust to check for any clogs

We CAN NOT run codes because car will not last long enough for us to pull the codes. Before it was dying it was throwing a TPS code so we replaced it. Still nothing. Check engine light came on a few days after this  starting happening.

Please help. I'll pay anything to get this issue fixed.
[SIGPIC][/SIGPIC]88 TBird-5.0 Cobra engine, Fresh Paint, BBK Cold Air Intake, Aluminum Driveshaft, Brian Crower Cam, Nitrous, 5 lug conversion, full cobra breaks/rims assembly, BBM shift kit, Maximum Motorsports Caster cambers/shocks/struts, Eibach Springs, Mass Air Flow Conversion, HEI Distributor, Compression rate 10:1, 2.25" dual Magnaflow glasspacks- Ford Motorsports short headers, 70 mm tbody/egr/upper, 1 inch spacer on manifold & more

302 Running like . Still can't find issue

Reply #1 –
If you have any suggestion post here or PM me.
[SIGPIC][/SIGPIC]88 TBird-5.0 Cobra engine, Fresh Paint, BBK Cold Air Intake, Aluminum Driveshaft, Brian Crower Cam, Nitrous, 5 lug conversion, full cobra breaks/rims assembly, BBM shift kit, Maximum Motorsports Caster cambers/shocks/struts, Eibach Springs, Mass Air Flow Conversion, HEI Distributor, Compression rate 10:1, 2.25" dual Magnaflow glasspacks- Ford Motorsports short headers, 70 mm tbody/egr/upper, 1 inch spacer on manifold & more

302 Running like . Still can't find issue

Reply #2 –
You don't have a vacuum to the MAP sensor do you? What is the timing set at? How did you set the timing? Are the spark plugs wet with gasoline? Maybe the FPR is no good.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

302 Running like . Still can't find issue

Reply #3 –
Hey vinnie! No vacuum up to MAP. Its got a small plug on it to cover it. Timing is something i have to re adjust today. Spark plugs do get wet with gas after each start. Fuel pressure regulator got replaced with a new one.
[SIGPIC][/SIGPIC]88 TBird-5.0 Cobra engine, Fresh Paint, BBK Cold Air Intake, Aluminum Driveshaft, Brian Crower Cam, Nitrous, 5 lug conversion, full cobra breaks/rims assembly, BBM shift kit, Maximum Motorsports Caster cambers/shocks/struts, Eibach Springs, Mass Air Flow Conversion, HEI Distributor, Compression rate 10:1, 2.25" dual Magnaflow glasspacks- Ford Motorsports short headers, 70 mm tbody/egr/upper, 1 inch spacer on manifold & more

302 Running like . Still can't find issue

Reply #4 –
Is everything stock?

When you turn the key on does the fuel pump run for two seconds and shut off?
This proves the program in the computer is running.

Check that the fuel pressure holds after you shut the engine off.
This will check if your injectors are sealing and not dumping in extra gas.

You can pull codes without the engine running.
It's called KOEO (Key On Engine Off) mode.
It will run tests and report codes and also read out codes in the computer memory.

302 Running like . Still can't find issue

Reply #5 –
You can pull stored codes from the memory, irregardless of engine running or not.
Always pull codes...always.
Do that, then get back to us with your findings.

EDIT: softtouch beat me lol.

Also, as Vinnie suggested, make sure your timing is set correctly. Pull the SPOUT connector before setting or resetting the timing. If the timing is off, throwing 250 dollars worth in new parts won't fix .

Timing.
Codes.
That will narrow it down by 75%.
'98 Explorer 5.0
'20 Malibu (I know, Chevy, but, 35MPG. Let's go brandon, eh)

302 Running like . Still can't find issue

Reply #6 –
Quote from: treflipboy;365608
Hey vinnie! No vacuum up to MAP. Its got a small plug on it to cover it.

If it's a BAP it has to be open to the atmosphere not plugged.

302 Running like . Still can't find issue

Reply #7 –
Quote from: softtouch;365615
If it's a BAP it has to be open to the atmosphere not plugged.

Exactly. It's probably not a cap, but a plastic part with a hole in it to prevent one from putting a vacuum tube on it.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

302 Running like . Still can't find issue

Reply #8 –
Its not a cap, but its correct. Its a small cover type thing so a vacuum doesn't go on it. Its a brand new one. I'll go pull some codes RIGHT now :)
[SIGPIC][/SIGPIC]88 TBird-5.0 Cobra engine, Fresh Paint, BBK Cold Air Intake, Aluminum Driveshaft, Brian Crower Cam, Nitrous, 5 lug conversion, full cobra breaks/rims assembly, BBM shift kit, Maximum Motorsports Caster cambers/shocks/struts, Eibach Springs, Mass Air Flow Conversion, HEI Distributor, Compression rate 10:1, 2.25" dual Magnaflow glasspacks- Ford Motorsports short headers, 70 mm tbody/egr/upper, 1 inch spacer on manifold & more

302 Running like . Still can't find issue

Reply #9 –
KEOE codes pulled
18- Loss of ignition
63- TPS
and 31 EGR valve position or exhaust


Brand new EGR and brand new TPS and also brand new ignition coil. I dont get it : /
[SIGPIC][/SIGPIC]88 TBird-5.0 Cobra engine, Fresh Paint, BBK Cold Air Intake, Aluminum Driveshaft, Brian Crower Cam, Nitrous, 5 lug conversion, full cobra breaks/rims assembly, BBM shift kit, Maximum Motorsports Caster cambers/shocks/struts, Eibach Springs, Mass Air Flow Conversion, HEI Distributor, Compression rate 10:1, 2.25" dual Magnaflow glasspacks- Ford Motorsports short headers, 70 mm tbody/egr/upper, 1 inch spacer on manifold & more

302 Running like . Still can't find issue

Reply #10 –
throttle position sensors have to be calibrated, i think...
'98 Explorer 5.0
'20 Malibu (I know, Chevy, but, 35MPG. Let's go brandon, eh)

302 Running like . Still can't find issue

Reply #11 –
The TPS was set to .98. Suggested =.96 (correct me if im wrong)

I had a fox mustang/tbird mechanic over here to help. He's a good friend of mine with 3 88 saleen mustang coupes (beautiful fkkn cars)

He knows his stuff, and we can't figure it out.

PLEASE feel free to brainstorm outloud. I'm willing to try anything. I've probably spent 20+ hours researching and 50 hours outside by the  car : /

This is literally taking up all my time and i'm getting sick of it.
[SIGPIC][/SIGPIC]88 TBird-5.0 Cobra engine, Fresh Paint, BBK Cold Air Intake, Aluminum Driveshaft, Brian Crower Cam, Nitrous, 5 lug conversion, full cobra breaks/rims assembly, BBM shift kit, Maximum Motorsports Caster cambers/shocks/struts, Eibach Springs, Mass Air Flow Conversion, HEI Distributor, Compression rate 10:1, 2.25" dual Magnaflow glasspacks- Ford Motorsports short headers, 70 mm tbody/egr/upper, 1 inch spacer on manifold & more

302 Running like . Still can't find issue

Reply #12 –
Is the Mass Air meter electronics or the car's computer bad?
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

302 Running like . Still can't find issue

Reply #13 –
Are the plug wires on in the right order? How are the fuel injectors/ Does the MAF match the injectors? What computer do you have in the car?
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

302 Running like . Still can't find issue

Reply #14 –
It could be injectors, try pulling a spark plug wire off one at a time,maybe you can isolate to a cylinder or two. I had to change my injectors recently for a similar problem, but not as bad. That code 18 would have me wondering.
Old Grey Cat to this.88 Cat, 5.0 HO, CW mounts, mass air, CI custom cam, afr165's, Tmoss worked cobra intake, BBK shorty's,off road h pipe, magnaflow ex. T-5,spec stage 2 clutch, 8.8 373 TC trac loc, che ajustables with bullits on the rear. 11" brakes up front. +