90 sidekick bogging down while accelerating

[lopezlv]

New to this but hope I can get help with my 1990 Sidekick. The engine starts to bog down after warming up on the road. When the engine is cold there is no problem but after awhile the engine will bog down as I try to accelerate. If I take my foot off the gas, the engine idles fine, its only after I press on the pedal when it happens. I changed the air and fuel filters as well as the sparkplugs, distrib cap and rotor. I also changed out the vacuum lines and checked the fuel injector. I have the 8valve 1.6 engine. Any help would be great.

[jtgh]

HELLO HOT BOGGER.

runs good cold
bogs hot.

8v = MAP TBI
key on , no start , CEL lamp ON..? must be.
no check engine light after starting? if on, then pull codes.
will WOT cure bog? HOT,, wide open throttle.

does engine get fully hot 180 to 200F

[lopezlv]

Hey JT. thanks for the quick response. CEL was blinking when I bought it. Was blinking 44 (idle switch in TP???). Crossed pins and got no other codes. disconnected batt and cleared codes (blinking 12 now). WOT still has bog and engine temp good (middle of temp guage). Runs like a champ when cold, can put about 50-60 highway miles before she starts to bog.

[jtgh]

90 8v bog.
here is your engine:
sensors>>>>>>> ECU [and perfect fuel pressure] >>>>>perfect AFR.

That's the EFI side.
then there is the engine.

is suspect fuel pressure is ok. (can flog the dog cold and it has power)

check engine compression and vacuum
engine 150psi cold or more, (can go to 190 on hot engine) .
vacuum solid not bumping at 19 HG inches.
( low compression , slipped timing belt)
solid vacuum shows, no leaking or sticking valves.

ok here is a test, all 8v have this MAP sensor.
make sure the vacuum is not blocked from manifold to this sensor, see filter there,
no blockage there either.
How is idle speeds?
next , pull the Evap hose ( it should suck air like crazy ) and instantly cause engine to race. if not MAP is sick.

Sick means , it can see the vacuum or is bad.

It really measure manifold pressure absolute but the confuse people so i say vacuum.

At wide open Throttle(wot) it see 14.7 PSI atomospheric pressure (almost 1 bar)

it can be tested with a voltmeter easy.
i have the spec on it.

to troubleshoot any engine, it is best to check engine basics first.
can it pump air.
compression test and vacuum test.

since yours makes full power cold, it is confusing.


watch them CEL Codes.
44 is gross idle switch open all the time,this will cause engine to stall at stop signs and the like. TPS switch is second function of TPS (out of 2)

your symptoms are interesting.